diff --git a/.gitignore b/.gitignore
--- a/.gitignore
+++ b/.gitignore
@@ -60,21 +60,23 @@
 eg/colin/*Funs
 eg/tri
 eg/bits
+eg/digits
 eg/peano
 eg/these
 eg/tuple
+eg/conditionals
 bench/carry-on
 bench/strategies
 bench/self
 bench/longshot
 bench/ill-hit
-bench/p12
-bench/p30
+bench/i12
+bench/i30
 bench/candidates
 bench/redundants
 bench/erroneous
 bench/gps
-bench/gps2
+bench/psb2
 bench/lowtests
 bench/terpret
 bench/weird
diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -43,9 +43,11 @@
   eg/bst \
   eg/tri \
   eg/bits \
+  eg/digits \
   eg/peano \
   eg/these \
   eg/tuple \
+  eg/conditionals \
   bench/candidates \
   bench/redundants \
   bench/erroneous \
@@ -55,10 +57,10 @@
   bench/strategies \
   bench/self \
   bench/carry-on \
-  bench/p12 \
-  bench/p30 \
+  bench/i12 \
+  bench/i30 \
   bench/gps \
-  bench/gps2 \
+  bench/psb2 \
   bench/terpret \
   bench/unique \
   bench/weird \
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -64,8 +64,8 @@
 addition, multiplication, subtraction and their neutral elements:
 
 	ingredients :: [Ingredient]
-	ingredients  =  [ unfun (0::Int)
-	                , unfun (1::Int)
+	ingredients  =  [ con (0::Int)
+	                , con (1::Int)
 	                , fun "+" ((+) :: Int -> Int -> Int)
 	                , fun "*" ((*) :: Int -> Int -> Int)
 	                , fun "-" ((-) :: Int -> Int -> Int)
@@ -121,9 +121,9 @@
 given list constructors, zero, one and subtraction:
 
 	> conjure "take" (take' :: Int -> [A] -> [A])
-	>   [ unfun (0 :: Int)
-	>   , unfun (1 :: Int)
-	>   , unfun ([] :: [A])
+	>   [ con (0 :: Int)
+	>   , con (1 :: Int)
+	>   , con ([] :: [A])
 	>   , fun ":" ((:) :: A -> [A] -> [A])
 	>   , fun "-" ((-) :: Int -> Int -> Int)
 	>   ]
@@ -176,7 +176,7 @@
 with the following call:
 
 	conjureFromSpec "duplicates" duplicatesSpec
-	  [ unfun ([] :: [Int])
+	  [ con ([] :: [Int])
 	  , fun "not" not
 	  , fun "&&" (&&)
 	  , fun ":" ((:) :: Int -> [Int] -> [Int])
diff --git a/TODO.md b/TODO.md
--- a/TODO.md
+++ b/TODO.md
@@ -7,14 +7,9 @@
   constructors that are not recursive.
   This change will need to be done in LeanCheck itself.
 
-* Detail two new proposed pruning rules from Colin.
-  (email from Feb 24 and follow-up in meeting)
-
 * Allow timeout setting?
 
-* Rethink Conjurable typeclass?
-
-* Allow chains of guards (see below).
+* Find most efficient of a given size (see below).
 
 * Better error reporting when `Listable` is out-of-scope when using `deriveConjurable`.
   This needs to be implemented on LeanCheck itself.
@@ -25,36 +20,11 @@
 	(qsort example)
 
 
-## Allow chains of guards
-
-With the use of `guard` right now,
-Conjure can generate functions such as the following:
-
-	function x y z
-	  | x < 123    =  ...
-	  | otherwise  =  ...
-
-We should probably allow chains of guards such as the following:
-
-	function x y z
-	  | x < 123    =  ...
-	  | x == 321   =  ...
-	  | y == 12    =  ...
-	  | otherwise  =  ...
-
-Internally, these are just chains of if-then-else applications:
-
-	function x y z  =  if x < 123
-	                   then ...
-					   else if x == 321
-					   then ...
-					   else if y == 12
-					   then ...
-					   else ...
+## Find the most efficient of a given size
 
-This change shouldn't be so complicated to introduce
-requiring a change in `enumerateAppsFor` relaxing `ufor hx`
-depending on what we have on the left...
+While evaluating candidates, we can count the number of matches in order to
+select the most efficient.  When actually conjuring, we always wait until the
+end of the current size to select the candidate with least evaluations.
 
 
 ## Forbid recursion into negatives
@@ -78,6 +48,19 @@
    This may require changing the format definitions themselves...
 2. use this on `showDefn` somehow
 3. use this on `toDynamicWithDefn` somehow
+
+Alternative: include the guard as part of the pattern "internally".  As if we
+had a n+k pattern.  Like so:
+
+	tri 1  =  1
+	tri x@(_ + 2)  =  x + tri (x - 1)
+
+When displaying of course, we remove the n+k pattern.
+
+This can be done as early as enumerating the possible patterns and should make
+things easier in `keepB`.  The matching engine would have to be customized
+somehow.  Maybe an `@`-named operator can adopt a special meaning in `Express`?
+
 
 
 This file is part of Conjure,
diff --git a/bench/candidates.hs b/bench/candidates.hs
--- a/bench/candidates.hs
+++ b/bench/candidates.hs
@@ -40,43 +40,43 @@
 main :: IO ()
 main  =  do
   printCandidates 9 6 "foo" (undefined :: Int -> Int)
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
 
   printCandidates 9 5 "?" (undefined :: Int -> Int -> Int)
-    [ unfun (0 :: Int)
+    [ con (0 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "dec" (subtract 1 :: Int -> Int)
     ]
 
   printCandidates 9 6 "goo" (undefined :: [Int] -> [Int])
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   printCandidates 9 6 "??" (undefined :: [Int] -> [Int] -> [Int])
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   printCandidates 9 6 "ton" (undefined :: Bool -> Bool)
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "not" not
     ]
 
   printCandidates 9 6 "&|" (undefined :: Bool -> Bool -> Bool)
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "not" not
@@ -88,6 +88,6 @@
   -- nevertheless useful for observing candidate filtering
   -- through other means
   printCandidates 9 6 "gcd" (undefined :: Int -> Int -> Int)
-    [ unfun (0::Int)
+    [ con (0::Int)
     , fun "`mod`" (mod :: Int -> Int -> Int)
     ]
diff --git a/bench/candidates.txt b/bench/candidates.txt
--- a/bench/candidates.txt
+++ b/bench/candidates.txt
@@ -95,5420 +95,5420 @@
 
 foo x  =  1 - x
 
-foo x  =  x * x - 1
-
-foo x  =  x + (x + x)
-
-foo x  =  x + (x + 1)
-
-foo x  =  x + (1 + 1)
-
-foo x  =  x + x * x
-
-foo x  =  x + (x - 1)
-
-foo x  =  x + (0 - 1)
-
-foo x  =  1 + (x + x)
-
-foo x  =  1 + (x + 1)
-
-foo x  =  1 + (1 + 1)
-
-foo x  =  1 + x * x
-
-foo x  =  1 + (0 - x)
-
-foo x  =  1 + (1 - x)
-
-foo x  =  x * (x + x)
-
-foo x  =  x * (x * x)
-
-foo x  =  x * (x - 1)
-
-foo x  =  x * (0 - x)
-
-foo x  =  x * (0 - 1)
-
-foo x  =  x * (1 - x)
-
-foo x  =  x - (x + x)
-
-foo x  =  x - (x + 1)
-
-foo x  =  x - (1 + 1)
-
-foo x  =  x - x * x
-
-foo x  =  0 - (x + x)
-
-foo x  =  0 - (x + 1)
-
-foo x  =  0 - (1 + 1)
-
-foo x  =  1 - (x + x)
-
-foo x  =  1 - (x + 1)
-
-foo x  =  1 - (1 + 1)
-
-foo x  =  1 - x * x
-
-
-pattern candidates:
-
-foo x  =  x
-
-foo x  =  0
-
-foo x  =  1
-
-foo 0  =  0
-foo x  =  1
-
-foo 0  =  1
-foo x  =  x
-
-foo 0  =  1
-foo x  =  0
-
-foo x  =  x + x
-
-foo x  =  x + 1
-
-foo x  =  x * x
-
-foo x  =  x - 1
-
-foo x  =  0 - x
-
-foo x  =  1 - x
-
-foo 1  =  0
-foo x  =  x
-
-foo 1  =  0
-foo x  =  1
-
-foo 1  =  1
-foo x  =  0
-
-foo 0  =  0
-foo x  =  x + 1
-
-foo 0  =  0
-foo x  =  x - 1
-
-foo 0  =  0
-foo x  =  1 - x
-
-foo 0  =  1
-foo x  =  x + x
-
-foo 0  =  1
-foo x  =  x * x
-
-foo 0  =  1
-foo x  =  x - 1
-
-foo 0  =  1
-foo x  =  0 - x
-
-foo 0  =  0
-foo 1  =  0
-foo x  =  1
-
-foo 0  =  1
-foo 1  =  0
-foo x  =  x
-
-foo 0  =  1
-foo 1  =  1
-foo x  =  0
-
-foo x  =  x * x - 1
-
-foo x  =  x + (x + x)
-
-foo x  =  x + (x + 1)
-
-foo x  =  x + x * x
-
-foo x  =  x + (x - 1)
-
-foo x  =  1 + (x + x)
-
-foo x  =  1 + (x + 1)
-
-foo x  =  1 + x * x
-
-foo x  =  1 + (0 - x)
-
-foo x  =  1 + (1 - x)
-
-foo x  =  x * (x + x)
-
-foo x  =  x * (x * x)
-
-foo x  =  x * (x - 1)
-
-foo x  =  x * (0 - x)
-
-foo x  =  x * (1 - x)
-
-foo x  =  x - (x + x)
-
-foo x  =  x - (x + 1)
-
-foo x  =  x - x * x
-
-foo x  =  0 - (x + x)
-
-foo x  =  0 - (x + 1)
-
-foo x  =  1 - (x + x)
-
-foo x  =  1 - (x + 1)
-
-foo x  =  1 - x * x
-
-foo 1  =  0
-foo x  =  x + x
-
-foo 1  =  0
-foo x  =  x + 1
-
-foo 1  =  0
-foo x  =  x * x
-
-foo 1  =  0
-foo x  =  0 - x
-
-foo 1  =  1
-foo x  =  x + x
-
-foo 1  =  1
-foo x  =  x + 1
-
-foo 1  =  1
-foo x  =  x - 1
-
-foo 1  =  1
-foo x  =  0 - x
-
-foo 1  =  1
-foo x  =  1 - x
-
-foo 0  =  0
-foo x  =  x * x - 1
-
-foo 0  =  0
-foo x  =  x + (x + 1)
-
-foo 0  =  0
-foo x  =  x + (x - 1)
-
-foo 0  =  0
-foo x  =  1 + (x + x)
-
-foo 0  =  0
-foo x  =  1 + (x + 1)
-
-foo 0  =  0
-foo x  =  1 + x * x
-
-foo 0  =  0
-foo x  =  1 + (0 - x)
-
-foo 0  =  0
-foo x  =  1 + (1 - x)
-
-foo 0  =  0
-foo x  =  x - (x + 1)
-
-foo 0  =  0
-foo x  =  0 - (x + 1)
-
-foo 0  =  0
-foo x  =  1 - (x + x)
-
-foo 0  =  0
-foo x  =  1 - x * x
-
-foo 0  =  1
-foo x  =  x * x - 1
-
-foo 0  =  1
-foo x  =  x + (x + x)
-
-foo 0  =  1
-foo x  =  x + x * x
-
-foo 0  =  1
-foo x  =  x + (x - 1)
-
-foo 0  =  1
-foo x  =  1 + (x + 1)
-
-foo 0  =  1
-foo x  =  1 + (1 - x)
-
-foo 0  =  1
-foo x  =  x * (x + x)
-
-foo 0  =  1
-foo x  =  x * (x * x)
-
-foo 0  =  1
-foo x  =  x * (x - 1)
-
-foo 0  =  1
-foo x  =  x * (0 - x)
-
-foo 0  =  1
-foo x  =  x * (1 - x)
-
-foo 0  =  1
-foo x  =  x - (x + x)
-
-foo 0  =  1
-foo x  =  x - (x + 1)
-
-foo 0  =  1
-foo x  =  x - x * x
-
-foo 0  =  1
-foo x  =  0 - (x + x)
-
-foo 0  =  1
-foo x  =  0 - (x + 1)
-
-foo 0  =  1
-foo x  =  1 - (x + 1)
-
-foo 0  =  0
-foo 1  =  0
-foo x  =  x + 1
-
-foo 0  =  0
-foo 1  =  1
-foo x  =  x + 1
-
-foo 0  =  0
-foo 1  =  1
-foo x  =  x - 1
-
-foo 0  =  0
-foo 1  =  1
-foo x  =  1 - x
-
-foo 0  =  1
-foo 1  =  0
-foo x  =  x + x
-
-foo 0  =  1
-foo 1  =  0
-foo x  =  x * x
-
-foo 0  =  1
-foo 1  =  0
-foo x  =  0 - x
-
-foo 0  =  1
-foo 1  =  1
-foo x  =  x + x
-
-foo 0  =  1
-foo 1  =  1
-foo x  =  x - 1
-
-foo 0  =  1
-foo 1  =  1
-foo x  =  0 - x
-
-
-
-allowed patterns:
-
-foo x  =  _
-
-
-foo 0  =  _
-foo x  =  _
-
-
-foo 1  =  _
-foo x  =  _
-
-
-foo 0  =  _
-foo 1  =  _
-foo x  =  _
-
-
-
-
-allowed deconstructions:
-
-_ - 1 :: Int
-
-Candidates for: ? :: Int -> Int -> Int
-  pruning with 13/34 rules
-  [3,3,9,18,60,162,489,1475,4619] direct candidates, 0 duplicates
-  [3,8,25,71,205,632,1957,5906,18303] pattern candidates, 0 duplicates
-
-rules:
-x * 0 == 0
-0 * x == 0
-x + 0 == x
-0 + x == x
-dec (x + y) == x + dec y
-dec (x + y) == y + dec x
-dec (x + y) == dec x + y
-dec (x + y) == dec y + x
-(x * y) * z == x * (y * z)
-(x * y) * z == y * (x * z)
-(x + y) + z == x + (y + z)
-(x + y) + z == y + (x + z)
-(x + x) * y == x * (y + y)
-equations:
-y * x == x * y
-y + x == x + y
-y + dec x == x + dec y
-dec x + y == x + dec y
-dec y + x == dec x + y
-x + dec 0 == dec x
-dec 0 + x == dec x
-y * (x * z) == x * (y * z)
-z * (x * y) == x * (y * z)
-z * (y * x) == x * (y * z)
-y + (x + z) == x + (y + z)
-z + (x + y) == x + (y + z)
-z + (y + x) == x + (y + z)
-(z + y) * x == x * (y + z)
-z * y + x == x + y * z
-y * (x + x) == x * (y + y)
-y + dec (dec x) == x + dec (dec y)
-dec (dec x) + y == x + dec (dec y)
-dec (dec y) + x == dec (dec x) + y
-x + dec (dec 0) == dec (dec x)
-dec (dec 0) + x == dec (dec x)
-
-direct candidates:
-
-x ? y  =  x
-
-x ? y  =  y
-
-x ? y  =  0
-
-x ? y  =  dec x
-
-x ? y  =  dec y
-
-x ? y  =  dec 0
-
-x ? y  =  x + x
-
-x ? y  =  x + y
-
-x ? y  =  y + y
-
-x ? y  =  x * x
-
-x ? y  =  x * y
-
-x ? y  =  y * y
-
-x ? y  =  dec (dec x)
-
-x ? y  =  dec (dec y)
-
-x ? y  =  dec (dec 0)
-
-x ? y  =  dec (x * x)
-
-x ? y  =  dec (x * y)
-
-x ? y  =  dec (y * y)
-
-x ? y  =  dec (dec (dec x))
-
-x ? y  =  dec (dec (dec y))
-
-x ? y  =  dec (dec (dec 0))
-
-x ? y  =  x + dec x
-
-x ? y  =  x + dec y
-
-x ? y  =  x + dec 0
-
-x ? y  =  y + dec x
-
-x ? y  =  y + dec y
-
-x ? y  =  y + dec 0
-
-x ? y  =  x * dec x
-
-x ? y  =  x * dec y
-
-x ? y  =  x * dec 0
-
-x ? y  =  y * dec x
-
-x ? y  =  y * dec y
-
-x ? y  =  y * dec 0
-
-x ? y  =  dec (dec (x * x))
-
-x ? y  =  dec (dec (x * y))
-
-x ? y  =  dec (dec (y * y))
-
-x ? y  =  dec (dec (dec (dec x)))
-
-x ? y  =  dec (dec (dec (dec y)))
-
-x ? y  =  dec (dec (dec (dec 0)))
-
-x ? y  =  dec (x * dec x)
-
-x ? y  =  dec (x * dec y)
-
-x ? y  =  dec (x * dec 0)
-
-x ? y  =  dec (y * dec x)
-
-x ? y  =  dec (y * dec y)
-
-x ? y  =  dec (y * dec 0)
-
-x ? y  =  x + (x + x)
-
-x ? y  =  x + (x + y)
-
-x ? y  =  x + (y + y)
-
-x ? y  =  x + x * x
-
-x ? y  =  x + x * y
-
-x ? y  =  x + y * y
-
-x ? y  =  x + dec (dec x)
-
-x ? y  =  x + dec (dec y)
-
-x ? y  =  x + dec (dec 0)
-
-x ? y  =  y + (x + x)
-
-x ? y  =  y + (x + y)
-
-x ? y  =  y + (y + y)
-
-x ? y  =  y + x * x
-
-x ? y  =  y + x * y
-
-x ? y  =  y + y * y
-
-x ? y  =  y + dec (dec x)
-
-x ? y  =  y + dec (dec y)
-
-x ? y  =  y + dec (dec 0)
-
-x ? y  =  x * (x + x)
-
-x ? y  =  x * (x + y)
-
-x ? y  =  x * (y + y)
-
-x ? y  =  x * (x * x)
-
-x ? y  =  x * (x * y)
-
-x ? y  =  x * (y * y)
-
-x ? y  =  x * dec (dec x)
-
-x ? y  =  x * dec (dec y)
-
-x ? y  =  x * dec (dec 0)
-
-x ? y  =  y * (x + x)
-
-x ? y  =  y * (x + y)
-
-x ? y  =  y * (y + y)
-
-x ? y  =  y * (x * x)
-
-x ? y  =  y * (x * y)
-
-x ? y  =  y * (y * y)
-
-x ? y  =  y * dec (dec x)
-
-x ? y  =  y * dec (dec y)
-
-x ? y  =  y * dec (dec 0)
-
-x ? y  =  dec x + dec x
-
-x ? y  =  dec x + dec y
-
-x ? y  =  dec x + dec 0
-
-x ? y  =  dec y + dec y
-
-x ? y  =  dec y + dec 0
-
-x ? y  =  dec 0 + dec 0
-
-x ? y  =  dec x * dec x
-
-x ? y  =  dec x * dec y
-
-x ? y  =  dec x * dec 0
-
-x ? y  =  dec y * dec y
-
-x ? y  =  dec y * dec 0
-
-x ? y  =  dec 0 * dec 0
-
-
-pattern candidates:
-
-x ? y  =  x
-
-x ? y  =  y
-
-x ? y  =  0
-
-x ? y  =  dec x
-
-x ? y  =  dec y
-
-x ? 0  =  x
-x ? y  =  y
-
-x ? 0  =  x
-x ? y  =  0
-
-x ? 0  =  0
-x ? y  =  x
-
-0 ? x  =  x
-x ? y  =  x
-
-0 ? x  =  x
-x ? y  =  0
-
-0 ? x  =  0
-x ? y  =  y
-
-x ? y  =  x + x
-
-x ? y  =  x + y
-
-x ? y  =  y + y
-
-x ? y  =  x * x
-
-x ? y  =  x * y
-
-x ? y  =  y * y
-
-x ? y  =  dec (dec x)
-
-x ? y  =  dec (dec y)
-
-x ? 0  =  x
-x ? y  =  dec x
-
-x ? 0  =  x
-x ? y  =  dec y
-
-x ? 0  =  0
-x ? y  =  dec x
-
-x ? 0  =  0
-x ? y  =  dec y
-
-x ? 0  =  dec x
-x ? y  =  x
-
-x ? 0  =  dec x
-x ? y  =  y
-
-x ? 0  =  dec x
-x ? y  =  0
-
-0 ? x  =  x
-x ? y  =  dec x
-
-0 ? x  =  x
-x ? y  =  dec y
-
-0 ? x  =  0
-x ? y  =  dec x
-
-0 ? x  =  0
-x ? y  =  dec y
-
-0 ? x  =  dec x
-x ? y  =  x
-
-0 ? x  =  dec x
-x ? y  =  y
-
-0 ? x  =  dec x
-x ? y  =  0
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  0
-
-0 ? x  =  x
-x ? 0  =  0
-x ? y  =  x
-
-0 ? x  =  0
-x ? 0  =  x
-x ? y  =  y
-
-x ? y  =  dec (x * x)
-
-x ? y  =  dec (x * y)
-
-x ? y  =  dec (y * y)
-
-x ? y  =  dec (dec (dec x))
-
-x ? y  =  dec (dec (dec y))
-
-x ? y  =  x + dec x
-
-x ? y  =  x + dec y
-
-x ? y  =  y + dec x
-
-x ? y  =  y + dec y
-
-x ? y  =  x * dec x
-
-x ? y  =  x * dec y
-
-x ? y  =  y * dec x
-
-x ? y  =  y * dec y
-
-x ? 0  =  x
-x ? y  =  x + x
-
-x ? 0  =  x
-x ? y  =  y + y
-
-x ? 0  =  x
-x ? y  =  x * x
-
-x ? 0  =  x
-x ? y  =  x * y
-
-x ? 0  =  x
-x ? y  =  y * y
-
-x ? 0  =  x
-x ? y  =  dec (dec x)
-
-x ? 0  =  x
-x ? y  =  dec (dec y)
-
-x ? 0  =  0
-x ? y  =  x + x
-
-x ? 0  =  0
-x ? y  =  x + y
-
-x ? 0  =  0
-x ? y  =  x * x
-
-x ? 0  =  0
-x ? y  =  dec (dec x)
-
-x ? 0  =  0
-x ? y  =  dec (dec y)
-
-x ? 0  =  dec x
-x ? y  =  dec y
-
-x ? 0  =  x + x
-x ? y  =  x
-
-x ? 0  =  x + x
-x ? y  =  y
-
-x ? 0  =  x + x
-x ? y  =  0
-
-x ? 0  =  x * x
-x ? y  =  x
-
-x ? 0  =  x * x
-x ? y  =  y
-
-x ? 0  =  x * x
-x ? y  =  0
-
-x ? 0  =  dec (dec x)
-x ? y  =  x
-
-x ? 0  =  dec (dec x)
-x ? y  =  y
-
-x ? 0  =  dec (dec x)
-x ? y  =  0
-
-0 ? x  =  x
-x ? y  =  x + x
-
-0 ? x  =  x
-x ? y  =  y + y
-
-0 ? x  =  x
-x ? y  =  x * x
-
-0 ? x  =  x
-x ? y  =  x * y
-
-0 ? x  =  x
-x ? y  =  y * y
-
-0 ? x  =  x
-x ? y  =  dec (dec x)
-
-0 ? x  =  x
-x ? y  =  dec (dec y)
-
-0 ? x  =  0
-x ? y  =  x + y
-
-0 ? x  =  0
-x ? y  =  y + y
-
-0 ? x  =  0
-x ? y  =  y * y
-
-0 ? x  =  0
-x ? y  =  dec (dec x)
-
-0 ? x  =  0
-x ? y  =  dec (dec y)
-
-0 ? x  =  dec x
-x ? y  =  dec x
-
-0 ? x  =  x + x
-x ? y  =  x
-
-0 ? x  =  x + x
-x ? y  =  y
-
-0 ? x  =  x + x
-x ? y  =  0
-
-0 ? x  =  x * x
-x ? y  =  x
-
-0 ? x  =  x * x
-x ? y  =  y
-
-0 ? x  =  x * x
-x ? y  =  0
-
-0 ? x  =  dec (dec x)
-x ? y  =  x
-
-0 ? x  =  dec (dec x)
-x ? y  =  y
-
-0 ? x  =  dec (dec x)
-x ? y  =  0
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  dec x
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  dec y
-
-0 ? x  =  x
-x ? 0  =  0
-x ? y  =  dec x
-
-0 ? x  =  x
-x ? 0  =  0
-x ? y  =  dec y
-
-0 ? x  =  x
-x ? 0  =  dec x
-x ? y  =  x
-
-0 ? x  =  x
-x ? 0  =  dec x
-x ? y  =  0
-
-0 ? x  =  0
-x ? 0  =  x
-x ? y  =  dec x
-
-0 ? x  =  0
-x ? 0  =  x
-x ? y  =  dec y
-
-0 ? x  =  0
-x ? 0  =  0
-x ? y  =  dec x
-
-0 ? x  =  0
-x ? 0  =  0
-x ? y  =  dec y
-
-0 ? x  =  0
-x ? 0  =  dec x
-x ? y  =  y
-
-0 ? x  =  dec x
-x ? 0  =  x
-x ? y  =  y
-
-0 ? x  =  dec x
-x ? 0  =  x
-x ? y  =  0
-
-0 ? x  =  dec x
-x ? 0  =  0
-x ? y  =  x
-
-x ? 0  =  x
-x ? y  =  x ? dec y
-
-x ? 0  =  x
-x ? y  =  y ? dec x
-
-x ? 0  =  x
-x ? y  =  y ? dec y
-
-x ? 0  =  x
-x ? y  =  0 ? dec y
-
-x ? 0  =  x
-x ? y  =  dec x ? x
-
-x ? 0  =  x
-x ? y  =  dec x ? y
-
-x ? 0  =  x
-x ? y  =  dec y ? x
-
-0 ? x  =  x
-x ? y  =  x ? dec y
-
-0 ? x  =  x
-x ? y  =  y ? dec x
-
-0 ? x  =  x
-x ? y  =  y ? dec y
-
-0 ? x  =  x
-x ? y  =  dec x ? x
-
-0 ? x  =  x
-x ? y  =  dec x ? y
-
-0 ? x  =  x
-x ? y  =  dec x ? 0
-
-0 ? x  =  x
-x ? y  =  dec y ? x
-
-x ? y  =  dec (dec (x * x))
-
-x ? y  =  dec (dec (x * y))
-
-x ? y  =  dec (dec (y * y))
-
-x ? y  =  dec (dec (dec (dec x)))
-
-x ? y  =  dec (dec (dec (dec y)))
-
-x ? y  =  dec (x * dec x)
-
-x ? y  =  dec (x * dec y)
-
-x ? y  =  dec (y * dec x)
-
-x ? y  =  dec (y * dec y)
-
-x ? y  =  x + (x + x)
-
-x ? y  =  x + (x + y)
-
-x ? y  =  x + (y + y)
-
-x ? y  =  x + x * x
-
-x ? y  =  x + x * y
-
-x ? y  =  x + y * y
-
-x ? y  =  x + dec (dec x)
-
-x ? y  =  x + dec (dec y)
-
-x ? y  =  y + (x + x)
-
-x ? y  =  y + (x + y)
-
-x ? y  =  y + (y + y)
-
-x ? y  =  y + x * x
-
-x ? y  =  y + x * y
-
-x ? y  =  y + y * y
-
-x ? y  =  y + dec (dec x)
-
-x ? y  =  y + dec (dec y)
-
-x ? y  =  x * (x + x)
-
-x ? y  =  x * (x + y)
-
-x ? y  =  x * (y + y)
-
-x ? y  =  x * (x * x)
-
-x ? y  =  x * (x * y)
-
-x ? y  =  x * (y * y)
-
-x ? y  =  x * dec (dec x)
-
-x ? y  =  x * dec (dec y)
-
-x ? y  =  y * (x + x)
-
-x ? y  =  y * (x + y)
-
-x ? y  =  y * (y + y)
-
-x ? y  =  y * (x * x)
-
-x ? y  =  y * (x * y)
-
-x ? y  =  y * (y * y)
-
-x ? y  =  y * dec (dec x)
-
-x ? y  =  y * dec (dec y)
-
-x ? y  =  dec x + dec x
-
-x ? y  =  dec x + dec y
-
-x ? y  =  dec y + dec y
-
-x ? y  =  dec x * dec x
-
-x ? y  =  dec x * dec y
-
-x ? y  =  dec y * dec y
-
-x ? 0  =  x
-x ? y  =  dec (x * x)
-
-x ? 0  =  x
-x ? y  =  dec (x * y)
-
-x ? 0  =  x
-x ? y  =  dec (y * y)
-
-x ? 0  =  x
-x ? y  =  dec (dec (dec x))
-
-x ? 0  =  x
-x ? y  =  dec (dec (dec y))
-
-x ? 0  =  x
-x ? y  =  x + dec x
-
-x ? 0  =  x
-x ? y  =  x + dec y
-
-x ? 0  =  x
-x ? y  =  y + dec x
-
-x ? 0  =  x
-x ? y  =  y + dec y
-
-x ? 0  =  x
-x ? y  =  x * dec x
-
-x ? 0  =  x
-x ? y  =  x * dec y
-
-x ? 0  =  x
-x ? y  =  y * dec x
-
-x ? 0  =  x
-x ? y  =  y * dec y
-
-x ? 0  =  0
-x ? y  =  dec (x * x)
-
-x ? 0  =  0
-x ? y  =  dec (x * y)
-
-x ? 0  =  0
-x ? y  =  dec (y * y)
-
-x ? 0  =  0
-x ? y  =  dec (dec (dec x))
-
-x ? 0  =  0
-x ? y  =  dec (dec (dec y))
-
-x ? 0  =  0
-x ? y  =  x + dec x
-
-x ? 0  =  0
-x ? y  =  x + dec y
-
-x ? 0  =  0
-x ? y  =  y + dec x
-
-x ? 0  =  0
-x ? y  =  y + dec y
-
-x ? 0  =  0
-x ? y  =  x * dec x
-
-x ? 0  =  0
-x ? y  =  x * dec y
-
-x ? 0  =  dec x
-x ? y  =  x + x
-
-x ? 0  =  dec x
-x ? y  =  x + y
-
-x ? 0  =  dec x
-x ? y  =  y + y
-
-x ? 0  =  dec x
-x ? y  =  x * x
-
-x ? 0  =  dec x
-x ? y  =  x * y
-
-x ? 0  =  dec x
-x ? y  =  y * y
-
-x ? 0  =  dec x
-x ? y  =  dec (dec x)
-
-x ? 0  =  dec x
-x ? y  =  dec (dec y)
-
-x ? 0  =  x + x
-x ? y  =  dec x
-
-x ? 0  =  x + x
-x ? y  =  dec y
-
-x ? 0  =  x * x
-x ? y  =  dec x
-
-x ? 0  =  x * x
-x ? y  =  dec y
-
-x ? 0  =  dec (dec x)
-x ? y  =  dec x
-
-x ? 0  =  dec (dec x)
-x ? y  =  dec y
-
-x ? 0  =  dec (x * x)
-x ? y  =  x
-
-x ? 0  =  dec (x * x)
-x ? y  =  y
-
-x ? 0  =  dec (x * x)
-x ? y  =  0
-
-x ? 0  =  dec (dec (dec x))
-x ? y  =  x
-
-x ? 0  =  dec (dec (dec x))
-x ? y  =  y
-
-x ? 0  =  dec (dec (dec x))
-x ? y  =  0
-
-x ? 0  =  x + dec x
-x ? y  =  x
-
-x ? 0  =  x + dec x
-x ? y  =  y
-
-x ? 0  =  x + dec x
-x ? y  =  0
-
-x ? 0  =  x * dec x
-x ? y  =  x
-
-x ? 0  =  x * dec x
-x ? y  =  y
-
-x ? 0  =  x * dec x
-x ? y  =  0
-
-0 ? x  =  x
-x ? y  =  dec (x * x)
-
-0 ? x  =  x
-x ? y  =  dec (x * y)
-
-0 ? x  =  x
-x ? y  =  dec (y * y)
-
-0 ? x  =  x
-x ? y  =  dec (dec (dec x))
-
-0 ? x  =  x
-x ? y  =  dec (dec (dec y))
-
-0 ? x  =  x
-x ? y  =  x + dec x
-
-0 ? x  =  x
-x ? y  =  x + dec y
-
-0 ? x  =  x
-x ? y  =  y + dec x
-
-0 ? x  =  x
-x ? y  =  y + dec y
-
-0 ? x  =  x
-x ? y  =  x * dec x
-
-0 ? x  =  x
-x ? y  =  x * dec y
-
-0 ? x  =  x
-x ? y  =  y * dec x
-
-0 ? x  =  x
-x ? y  =  y * dec y
-
-0 ? x  =  0
-x ? y  =  dec (x * x)
-
-0 ? x  =  0
-x ? y  =  dec (x * y)
-
-0 ? x  =  0
-x ? y  =  dec (y * y)
-
-0 ? x  =  0
-x ? y  =  dec (dec (dec x))
-
-0 ? x  =  0
-x ? y  =  dec (dec (dec y))
-
-0 ? x  =  0
-x ? y  =  x + dec x
-
-0 ? x  =  0
-x ? y  =  x + dec y
-
-0 ? x  =  0
-x ? y  =  y + dec x
-
-0 ? x  =  0
-x ? y  =  y + dec y
-
-0 ? x  =  0
-x ? y  =  y * dec x
-
-0 ? x  =  0
-x ? y  =  y * dec y
-
-0 ? x  =  dec x
-x ? y  =  x + x
-
-0 ? x  =  dec x
-x ? y  =  x + y
-
-0 ? x  =  dec x
-x ? y  =  y + y
-
-0 ? x  =  dec x
-x ? y  =  x * x
-
-0 ? x  =  dec x
-x ? y  =  x * y
-
-0 ? x  =  dec x
-x ? y  =  y * y
-
-0 ? x  =  dec x
-x ? y  =  dec (dec x)
-
-0 ? x  =  dec x
-x ? y  =  dec (dec y)
-
-0 ? x  =  x + x
-x ? y  =  dec x
-
-0 ? x  =  x + x
-x ? y  =  dec y
-
-0 ? x  =  x * x
-x ? y  =  dec x
-
-0 ? x  =  x * x
-x ? y  =  dec y
-
-0 ? x  =  dec (dec x)
-x ? y  =  dec x
-
-0 ? x  =  dec (dec x)
-x ? y  =  dec y
-
-0 ? x  =  dec (x * x)
-x ? y  =  x
-
-0 ? x  =  dec (x * x)
-x ? y  =  y
-
-0 ? x  =  dec (x * x)
-x ? y  =  0
-
-0 ? x  =  dec (dec (dec x))
-x ? y  =  x
-
-0 ? x  =  dec (dec (dec x))
-x ? y  =  y
-
-0 ? x  =  dec (dec (dec x))
-x ? y  =  0
-
-0 ? x  =  x + dec x
-x ? y  =  x
-
-0 ? x  =  x + dec x
-x ? y  =  y
-
-0 ? x  =  x + dec x
-x ? y  =  0
-
-0 ? x  =  x * dec x
-x ? y  =  x
-
-0 ? x  =  x * dec x
-x ? y  =  y
-
-0 ? x  =  x * dec x
-x ? y  =  0
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  x + x
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  y + y
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  x * x
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  x * y
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  y * y
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  dec (dec x)
-
-0 ? x  =  x
-x ? 0  =  x
-x ? y  =  dec (dec y)
-
-0 ? x  =  x
-x ? 0  =  0
-x ? y  =  x + x
-
-0 ? x  =  x
-x ? 0  =  0
-x ? y  =  x * x
-
-0 ? x  =  x
-x ? 0  =  0
-x ? y  =  dec (dec x)
-
-0 ? x  =  x
-x ? 0  =  0
-x ? y  =  dec (dec y)
-
-0 ? x  =  x
-x ? 0  =  dec x
-x ? y  =  dec y
-
-0 ? x  =  x
-x ? 0  =  x + x
-x ? y  =  x
-
-0 ? x  =  x
-x ? 0  =  x + x
-x ? y  =  0
-
-0 ? x  =  x
-x ? 0  =  x * x
-x ? y  =  x
-
-0 ? x  =  x
-x ? 0  =  x * x
-x ? y  =  0
-
-0 ? x  =  x
-x ? 0  =  dec (dec x)
-x ? y  =  x
-
-0 ? x  =  x
-x ? 0  =  dec (dec x)
-x ? y  =  0
-
-0 ? x  =  0
-x ? 0  =  x
-x ? y  =  y + y
-
-0 ? x  =  0
-x ? 0  =  x
-x ? y  =  y * y
-
-0 ? x  =  0
-x ? 0  =  x
-x ? y  =  dec (dec x)
-
-0 ? x  =  0
-x ? 0  =  x
-x ? y  =  dec (dec y)
-
-0 ? x  =  0
-x ? 0  =  0
-x ? y  =  x + y
-
-0 ? x  =  0
-x ? 0  =  0
-x ? y  =  dec (dec x)
-
-0 ? x  =  0
-x ? 0  =  0
-x ? y  =  dec (dec y)
-
-0 ? x  =  0
-x ? 0  =  dec x
-x ? y  =  dec y
-
-0 ? x  =  0
-x ? 0  =  x + x
-x ? y  =  y
-
-0 ? x  =  0
-x ? 0  =  x * x
-x ? y  =  y
-
-0 ? x  =  0
-x ? 0  =  dec (dec x)
-x ? y  =  y
-
-0 ? x  =  dec x
-x ? 0  =  x
-x ? y  =  dec x
-
-0 ? x  =  dec x
-x ? 0  =  0
-x ? y  =  dec x
-
-0 ? x  =  dec x
-x ? 0  =  dec x
-x ? y  =  x
-
-0 ? x  =  dec x
-x ? 0  =  dec x
-x ? y  =  y
-
-0 ? x  =  dec x
-x ? 0  =  dec x
-x ? y  =  0
-
-0 ? x  =  x + x
-x ? 0  =  x
-x ? y  =  y
-
-0 ? x  =  x + x
-x ? 0  =  x
-x ? y  =  0
-
-0 ? x  =  x + x
-x ? 0  =  0
-x ? y  =  x
-
-0 ? x  =  x * x
-x ? 0  =  x
-x ? y  =  y
-
-0 ? x  =  x * x
-x ? 0  =  x
-x ? y  =  0
-
-0 ? x  =  x * x
-x ? 0  =  0
-x ? y  =  x
-
-0 ? x  =  dec (dec x)
-x ? 0  =  x
-x ? y  =  y
-
-0 ? x  =  dec (dec x)
-x ? 0  =  x
-x ? y  =  0
-
-0 ? x  =  dec (dec x)
-x ? 0  =  0
-x ? y  =  x
-
-0 ? 0  =  0
-0 ? x  =  dec x
-x ? y  =  dec x
-
-
-
-allowed patterns:
-
-x ? y  =  _
-
-
-x ? 0  =  _
-x ? y  =  _
-
-0 ? x  =  _
-x ? y  =  _
-
-
-0 ? x  =  _
-x ? 0  =  _
-x ? y  =  _
-
-0 ? 0  =  _
-0 ? x  =  _
-x ? y  =  _
-
-
-0 ? 0  =  _
-0 ? x  =  _
-x ? 0  =  _
-x ? y  =  _
-
-
-
-
-allowed deconstructions:
-
-dec _ :: Int
-dec (dec _) :: Int
-dec (dec (dec _)) :: Int
-
-Candidates for: goo :: [Int] -> [Int]
-  pruning with 4/4 rules
-  [2,0,1,0,1,0,1,0,1] direct candidates, 0 duplicates
-  [2,1,1,3,4,7,10,17,26] pattern candidates, 0 duplicates
-
-rules:
-xs ++ [] == xs
-[] ++ xs == xs
-(xs ++ ys) ++ zs == xs ++ (ys ++ zs)
-(x:xs) ++ ys == x:(xs ++ ys)
-
-direct candidates:
-
-goo xs  =  xs
-
-goo xs  =  []
-
-goo xs  =  xs ++ xs
-
-goo xs  =  xs ++ (xs ++ xs)
-
-
-pattern candidates:
-
-goo xs  =  xs
-
-goo xs  =  []
-
-goo []  =  []
-goo (x:xs)  =  xs
-
-goo xs  =  xs ++ xs
-
-goo []  =  []
-goo (x:xs)  =  x:xs
-
-goo []  =  []
-goo (x:xs)  =  [x]
-
-goo []  =  []
-goo (x:xs)  =  xs ++ xs
-
-goo []  =  []
-goo (x:xs)  =  x:goo xs
-
-goo []  =  []
-goo (x:xs)  =  xs ++ goo xs
-
-goo []  =  []
-goo (x:xs)  =  goo xs ++ xs
-
-goo xs  =  xs ++ (xs ++ xs)
-
-goo []  =  []
-goo (x:xs)  =  goo xs ++ goo xs
-
-goo []  =  []
-goo (x:xs)  =  x:x:xs
-
-goo []  =  []
-goo (x:xs)  =  [x,x]
-
-goo []  =  []
-goo (x:xs)  =  x:(xs ++ xs)
-
-goo []  =  []
-goo (x:xs)  =  xs ++ (x:xs)
-
-goo []  =  []
-goo (x:xs)  =  xs ++ [x]
-
-goo []  =  []
-goo (x:xs)  =  xs ++ (xs ++ xs)
-
-
-
-allowed patterns:
-
-goo xs  =  _
-
-
-goo []  =  _
-goo (x:xs)  =  _
-
-
-
-
-allowed deconstructions:
-
-
-Candidates for: ?? :: [Int] -> [Int] -> [Int]
-  pruning with 4/4 rules
-  [3,0,4,0,8,0,16,0,32] direct candidates, 0 duplicates
-  [3,8,15,45,127,268,845,1565,5692] pattern candidates, 0 duplicates
-
-rules:
-xs ++ [] == xs
-[] ++ xs == xs
-(xs ++ ys) ++ zs == xs ++ (ys ++ zs)
-(x:xs) ++ ys == x:(xs ++ ys)
-
-direct candidates:
-
-xs ?? ys  =  xs
-
-xs ?? ys  =  ys
-
-xs ?? ys  =  []
-
-xs ?? ys  =  xs ++ xs
-
-xs ?? ys  =  xs ++ ys
-
-xs ?? ys  =  ys ++ xs
-
-xs ?? ys  =  ys ++ ys
-
-xs ?? ys  =  xs ++ (xs ++ xs)
-
-xs ?? ys  =  xs ++ (xs ++ ys)
-
-xs ?? ys  =  xs ++ (ys ++ xs)
-
-xs ?? ys  =  xs ++ (ys ++ ys)
-
-xs ?? ys  =  ys ++ (xs ++ xs)
-
-xs ?? ys  =  ys ++ (xs ++ ys)
-
-xs ?? ys  =  ys ++ (ys ++ xs)
-
-xs ?? ys  =  ys ++ (ys ++ ys)
-
-
-pattern candidates:
-
-xs ?? ys  =  xs
-
-xs ?? ys  =  ys
-
-xs ?? ys  =  []
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  []
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  []
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys
-
-xs ?? ys  =  xs ++ xs
-
-xs ?? ys  =  xs ++ ys
-
-xs ?? ys  =  ys ++ xs
-
-xs ?? ys  =  ys ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  []
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ?? xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [] ?? xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [] ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ?? []
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [x]
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  [x]
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ ys
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  xs
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  ys
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  [x]
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  [x]
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ ys
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  xs
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  ys
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ?? []
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ?? []
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ?? []
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ?? []
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ?? []
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  xs ?? xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  xs ?? ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  xs ?? []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  ys ?? xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  ys ?? []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  [] ?? xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  [] ?? ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? xs
-(x:xs) ?? ys  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? []
-(x:xs) ?? ys  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [] ?? xs
-(x:xs) ?? ys  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? xs
-(x:xs) ?? ys  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? []
-(x:xs) ?? ys  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [] ?? xs
-(x:xs) ?? ys  =  ys
-
-xs ?? ys  =  xs ++ (xs ++ xs)
-
-xs ?? ys  =  xs ++ (xs ++ ys)
-
-xs ?? ys  =  xs ++ (ys ++ xs)
-
-xs ?? ys  =  xs ++ (ys ++ ys)
-
-xs ?? ys  =  ys ++ (xs ++ xs)
-
-xs ?? ys  =  ys ++ (xs ++ ys)
-
-xs ?? ys  =  ys ++ (ys ++ xs)
-
-xs ?? ys  =  ys ++ (ys ++ ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  x:xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  x:ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  [x]
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  y:xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  y:ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  [y]
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  x:xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  x:ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  [x]
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  y:xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  y:ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  [y]
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  x:xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  x:xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  x:xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  [x]
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  [x]
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  [x]
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ++ xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ++ xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ++ xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  x:xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  x:ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  [x]
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  y:xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  y:ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  [y]
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  x:xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  x:ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  [x]
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  y:xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  y:ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  [y]
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  x:xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  x:xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  x:xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  [x]
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  [x]
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  [x]
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ++ xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ++ xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ++ xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  x:xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  x:ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  [x]
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  xs ++ xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  xs ++ ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  ys ++ xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  ys ++ ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  x:xs
-(x:xs) ?? ys  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  x:xs
-(x:xs) ?? ys  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  x:xs
-(x:xs) ?? ys  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [x]
-(x:xs) ?? ys  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [x]
-(x:xs) ?? ys  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [x]
-(x:xs) ?? ys  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ++ xs
-(x:xs) ?? ys  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ++ xs
-(x:xs) ?? ys  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ++ xs
-(x:xs) ?? ys  =  []
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  (x:xs) ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  (x:ys) ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [x] ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  (xs ++ xs) ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  (xs ++ ys) ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  (ys ++ xs) ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  (ys ++ ys) ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? (x:xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? (x:ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? [x]
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? (xs ++ xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? (xs ++ ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? (ys ++ xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? (ys ++ ys)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:xs ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:ys ?? xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:ys ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:[] ?? xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:[] ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ xs ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ ys ?? xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ ys ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ [] ?? xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ [] ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ xs ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ ys ?? xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ ys ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ [] ?? xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ [] ?? ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ?? ys ++ xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ?? xs ++ xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ?? ys ++ xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [] ?? xs ++ xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [] ?? ys ++ xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ?? ys ++ ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ?? xs ++ ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ?? ys ++ ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [] ?? xs ++ ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [] ?? ys ++ ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:xs ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:ys ?? xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:ys ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:[] ?? xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:[] ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ xs ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ ys ?? xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ ys ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ [] ?? xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ [] ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ xs ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ ys ?? xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ ys ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ [] ?? xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ [] ?? ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ?? ys ++ xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ?? xs ++ xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ?? ys ++ xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  [] ?? xs ++ xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  [] ?? ys ++ xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ?? ys ++ ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ?? xs ++ ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ?? ys ++ ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  [] ?? xs ++ ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  [] ?? ys ++ ys
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  xs ?? ys
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  ys ?? xs
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  ys ?? ys
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  [] ?? xs
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  [] ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:xs ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:xs ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:xs ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:ys ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:ys ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ xs ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ xs ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ xs ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ ys ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ ys ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ xs ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ xs ?? ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ xs ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ ys ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ ys ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? xs ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? ys ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? [] ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ?? xs ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ?? [] ++ xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? xs ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? ys ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ?? [] ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ?? xs ++ ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ?? [] ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:xs ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:xs ?? ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:xs ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:ys ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:ys ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ xs ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ xs ?? ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ xs ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ ys ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ ys ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ xs ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ xs ?? ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ xs ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ ys ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ ys ?? []
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ?? xs ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ?? ys ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ?? [] ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ?? xs ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ?? [] ++ xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ?? xs ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ?? ys ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ?? [] ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ?? xs ++ ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ?? [] ++ ys
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  xs ?? xs
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  xs ?? ys
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  xs ?? []
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  ys ?? xs
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  ys ?? []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  [] ?? xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  [] ?? ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs ?? []
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  [] ?? xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs ?? []
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  [] ?? xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [] ?? xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [] ?? xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:x:xs
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:x:ys
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  [x,x]
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:(xs ++ xs)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:(xs ++ ys)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:(ys ++ xs)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  x:(ys ++ ys)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ (x:xs)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ (x:ys)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ [x]
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ (xs ++ xs)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ (xs ++ ys)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ (ys ++ xs)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  xs ++ (ys ++ ys)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ (x:xs)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ (x:ys)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ [x]
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ (xs ++ xs)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ (xs ++ ys)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ (ys ++ xs)
-
-xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ++ (ys ++ ys)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:x:xs
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:x:ys
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  [x,x]
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:(xs ++ xs)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:(xs ++ ys)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:(ys ++ xs)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  x:(ys ++ ys)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ (x:xs)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ (x:ys)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ [x]
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ (xs ++ xs)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ (xs ++ ys)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ (ys ++ xs)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  xs ++ (ys ++ ys)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ (x:xs)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ (x:ys)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ [x]
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ (xs ++ xs)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ (xs ++ ys)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ (ys ++ xs)
-
-xs ?? []  =  []
-xs ?? (x:ys)  =  ys ++ (ys ++ ys)
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  x:xs
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  x:ys
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  [x]
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  xs ++ ys
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  ys ++ xs
-
-xs ?? []  =  xs ++ xs
-xs ?? (x:ys)  =  ys ++ ys
-
-xs ?? []  =  xs ++ (xs ++ xs)
-xs ?? (x:ys)  =  xs
-
-xs ?? []  =  xs ++ (xs ++ xs)
-xs ?? (x:ys)  =  ys
-
-xs ?? []  =  xs ++ (xs ++ xs)
-xs ?? (x:ys)  =  []
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:x:xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:x:ys
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  [x,x]
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:(xs ++ xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:(xs ++ ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:(ys ++ xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  x:(ys ++ ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ (x:xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ (x:ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ [x]
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ (xs ++ xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ (xs ++ ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ (ys ++ xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  xs ++ (ys ++ ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ (x:xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ (x:ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ [x]
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ (xs ++ xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ (xs ++ ys)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ (ys ++ xs)
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ++ (ys ++ ys)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:x:xs
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:x:ys
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  [x,x]
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:(xs ++ xs)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:(xs ++ ys)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:(ys ++ xs)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  x:(ys ++ ys)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ (x:xs)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ (x:ys)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ [x]
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ (xs ++ xs)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ (xs ++ ys)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ (ys ++ xs)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  xs ++ (ys ++ ys)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ (x:xs)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ (x:ys)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ [x]
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ (xs ++ xs)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ (xs ++ ys)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ (ys ++ xs)
-
-[] ?? xs  =  []
-(x:xs) ?? ys  =  ys ++ (ys ++ ys)
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  x:xs
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  x:ys
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  [x]
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  xs ++ xs
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  xs ++ ys
-
-[] ?? xs  =  xs ++ xs
-(x:xs) ?? ys  =  ys ++ xs
-
-[] ?? xs  =  xs ++ (xs ++ xs)
-(x:xs) ?? ys  =  xs
-
-[] ?? xs  =  xs ++ (xs ++ xs)
-(x:xs) ?? ys  =  ys
-
-[] ?? xs  =  xs ++ (xs ++ xs)
-(x:xs) ?? ys  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  x:xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  x:ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  [x]
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  y:xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  y:ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  [y]
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ++ xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ++ ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ++ xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ++ ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  x:xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  x:xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  [x]
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  [x]
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs ++ xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? []  =  xs ++ xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  x:xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  x:xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [x]
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  [x]
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ++ xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ++ xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  []
-
-
-
-allowed patterns:
-
-xs ?? ys  =  _
-
-
-xs ?? []  =  _
-xs ?? (x:ys)  =  _
-
-[] ?? xs  =  _
-(x:xs) ?? ys  =  _
-
-
-[] ?? xs  =  _
-(x:xs) ?? []  =  _
-(x:xs) ?? (y:ys)  =  _
-
-[] ?? []  =  _
-[] ?? (x:xs)  =  _
-(x:xs) ?? ys  =  _
-
-
-[] ?? []  =  _
-[] ?? (x:xs)  =  _
-(x:xs) ?? []  =  _
-(x:xs) ?? (y:ys)  =  _
-
-
-
-
-allowed deconstructions:
-
-
-Candidates for: ton :: Bool -> Bool
-  pruning with 39/49 rules
-  [3,1,0,0,0,0,0,0,0] direct candidates, 0 duplicates
-  [3,3,0,0,0,0,0,0,0] pattern candidates, 0 duplicates
-
-rules:
-not False == True
-not True == False
-p && p == p
-p || p == p
-not (not p) == p
-p && False == False
-p && True == p
-False && p == False
-True && p == p
-p || False == p
-p || True == True
-False || p == p
-True || p == True
-not (p && q) == not p || not q
-not (p && q) == not q || not p
-not (p || q) == not p && not q
-not (p || q) == not q && not p
-p && not p == False
-not p && p == False
-p || not p == True
-not p || p == True
-(p && q) && r == p && (q && r)
-(p && q) && r == q && (p && r)
-(p || q) || r == p || (q || r)
-(p || q) || r == q || (p || r)
-p && (p && q) == p && q
-p && (q && p) == p && q
-p && (q && p) == q && p
-p || (p || q) == p || q
-p || (q || p) == p || q
-p || (q || p) == q || p
-p && (p || q) == p
-p && (q || p) == p
-(p || q) && p == p
-(p || q) && q == q
-p || p && q == p
-p || q && p == p
-p && q || p == p
-p && q || q == q
-equations:
-q && p == p && q
-q || p == p || q
-q && (p && r) == p && (q && r)
-r && (p && q) == p && (q && r)
-r && (q && p) == p && (q && r)
-q || (p || r) == p || (q || r)
-r || (p || q) == p || (q || r)
-r || (q || p) == p || (q || r)
-(r || q) && p == p && (q || r)
-r && q || p == p || q && r
-
-direct candidates:
-
-ton p  =  p
-
-ton p  =  False
-
-ton p  =  True
-
-ton p  =  not p
-
-
-pattern candidates:
-
-ton p  =  p
-
-ton p  =  False
-
-ton p  =  True
-
-ton p  =  not p
-
-ton False  =  False
-ton True  =  True
-
-ton False  =  True
-ton True  =  False
-
-
-
-allowed patterns:
-
-ton p  =  _
-
-
-ton False  =  _
-ton True  =  _
-
-
-
-
-allowed deconstructions:
-
-
-Candidates for: &| :: Bool -> Bool -> Bool
-  pruning with 39/49 rules
-  [4,2,2,4,2,16,17,56,110] direct candidates, 0 duplicates
-  [4,14,26,10,2,16,17,56,110] pattern candidates, 0 duplicates
-
-rules:
-not False == True
-not True == False
-p && p == p
-p || p == p
-not (not p) == p
-p && False == False
-p && True == p
-False && p == False
-True && p == p
-p || False == p
-p || True == True
-False || p == p
-True || p == True
-not (p && q) == not p || not q
-not (p && q) == not q || not p
-not (p || q) == not p && not q
-not (p || q) == not q && not p
-p && not p == False
-not p && p == False
-p || not p == True
-not p || p == True
-(p && q) && r == p && (q && r)
-(p && q) && r == q && (p && r)
-(p || q) || r == p || (q || r)
-(p || q) || r == q || (p || r)
-p && (p && q) == p && q
-p && (q && p) == p && q
-p && (q && p) == q && p
-p || (p || q) == p || q
-p || (q || p) == p || q
-p || (q || p) == q || p
-p && (p || q) == p
-p && (q || p) == p
-(p || q) && p == p
-(p || q) && q == q
-p || p && q == p
-p || q && p == p
-p && q || p == p
-p && q || q == q
-equations:
-q && p == p && q
-q || p == p || q
-q && (p && r) == p && (q && r)
-r && (p && q) == p && (q && r)
-r && (q && p) == p && (q && r)
-q || (p || r) == p || (q || r)
-r || (p || q) == p || (q || r)
-r || (q || p) == p || (q || r)
-(r || q) && p == p && (q || r)
-r && q || p == p || q && r
-
-direct candidates:
-
-p &| q  =  p
-
-p &| q  =  q
-
-p &| q  =  False
-
-p &| q  =  True
-
-p &| q  =  not p
-
-p &| q  =  not q
-
-p &| q  =  p && q
-
-p &| q  =  p || q
-
-p &| q  =  p && not q
-
-p &| q  =  q && not p
-
-p &| q  =  p || not q
-
-p &| q  =  q || not p
-
-p &| q  =  not p && not q
-
-p &| q  =  not p || not q
-
-p &| q  =  p && (q && not p)
-
-p &| q  =  p && (q || not p)
-
-p &| q  =  q && (p && not q)
-
-p &| q  =  q && (p || not q)
-
-p &| q  =  p || q && not p
-
-p &| q  =  p || (q || not p)
-
-p &| q  =  q || p && not q
-
-p &| q  =  q || (p || not q)
-
-p &| q  =  not p && (p && q)
-
-p &| q  =  not p && (p || q)
-
-p &| q  =  not q && (p && q)
-
-p &| q  =  not q && (p || q)
-
-p &| q  =  not p || p && q
-
-p &| q  =  not p || (p || q)
-
-p &| q  =  not q || p && q
-
-p &| q  =  not q || (p || q)
-
-
-pattern candidates:
-
-p &| q  =  p
-
-p &| q  =  q
-
-p &| q  =  False
-
-p &| q  =  True
-
-p &| q  =  not p
-
-p &| q  =  not q
-
-p &| False  =  p
-p &| True  =  False
-
-p &| False  =  p
-p &| True  =  True
-
-p &| False  =  False
-p &| True  =  p
-
-p &| False  =  False
-p &| True  =  True
-
-p &| False  =  True
-p &| True  =  p
-
-p &| False  =  True
-p &| True  =  False
-
-False &| p  =  p
-True &| p  =  False
-
-False &| p  =  p
-True &| p  =  True
-
-False &| p  =  False
-True &| p  =  p
-
-False &| p  =  False
-True &| p  =  True
-
-False &| p  =  True
-True &| p  =  p
-
-False &| p  =  True
-True &| p  =  False
-
-p &| q  =  p && q
-
-p &| q  =  p || q
-
-p &| False  =  p
-p &| True  =  not p
-
-p &| False  =  False
-p &| True  =  not p
-
-p &| False  =  True
-p &| True  =  not p
-
-p &| False  =  not p
-p &| True  =  p
-
-p &| False  =  not p
-p &| True  =  False
-
-p &| False  =  not p
-p &| True  =  True
-
-False &| p  =  p
-True &| p  =  not p
-
-False &| p  =  False
-True &| p  =  not p
-
-False &| p  =  True
-True &| p  =  not p
-
-False &| p  =  not p
-True &| p  =  p
-
-False &| p  =  not p
-True &| p  =  False
-
-False &| p  =  not p
-True &| p  =  True
-
-False &| p  =  p
-True &| False  =  False
-True &| True  =  True
-
-False &| p  =  p
-True &| False  =  True
-True &| True  =  False
-
-False &| p  =  False
-True &| False  =  False
-True &| True  =  True
-
-False &| p  =  False
-True &| False  =  True
-True &| True  =  False
-
-False &| p  =  True
-True &| False  =  False
-True &| True  =  True
-
-False &| p  =  True
-True &| False  =  True
-True &| True  =  False
-
-False &| False  =  False
-False &| True  =  True
-True &| p  =  p
-
-False &| False  =  False
-False &| True  =  True
-True &| p  =  False
-
-False &| False  =  False
-False &| True  =  True
-True &| p  =  True
-
-False &| False  =  True
-False &| True  =  False
-True &| p  =  p
-
-False &| False  =  True
-False &| True  =  False
-True &| p  =  False
-
-False &| False  =  True
-False &| True  =  False
-True &| p  =  True
-
-p &| q  =  p && not q
-
-p &| q  =  q && not p
-
-p &| q  =  p || not q
-
-p &| q  =  q || not p
-
-False &| p  =  not p
-True &| False  =  False
-True &| True  =  True
-
-False &| p  =  not p
-True &| False  =  True
-True &| True  =  False
-
-False &| False  =  False
-False &| True  =  True
-True &| p  =  not p
-
-False &| False  =  True
-False &| True  =  False
-True &| p  =  not p
-
-False &| False  =  False
-False &| True  =  True
-True &| False  =  True
-True &| True  =  False
-
-False &| False  =  True
-False &| True  =  False
-True &| False  =  False
-True &| True  =  True
-
-p &| q  =  not p && not q
-
-p &| q  =  not p || not q
-
-p &| q  =  p && (q && not p)
-
-p &| q  =  p && (q || not p)
-
-p &| q  =  q && (p && not q)
-
-p &| q  =  q && (p || not q)
-
-p &| q  =  p || q && not p
-
-p &| q  =  p || (q || not p)
-
-p &| q  =  q || p && not q
-
-p &| q  =  q || (p || not q)
-
-p &| q  =  not p && (p && q)
-
-p &| q  =  not p && (p || q)
-
-p &| q  =  not q && (p && q)
-
-p &| q  =  not q && (p || q)
-
-p &| q  =  not p || p && q
-
-p &| q  =  not p || (p || q)
-
-p &| q  =  not q || p && q
-
-p &| q  =  not q || (p || q)
-
-
-
-allowed patterns:
-
-p &| q  =  _
-
-
-p &| False  =  _
-p &| True  =  _
-
-False &| p  =  _
-True &| p  =  _
-
-
-False &| p  =  _
-True &| False  =  _
-True &| True  =  _
-
-False &| False  =  _
-False &| True  =  _
-True &| p  =  _
-
-
-False &| False  =  _
-False &| True  =  _
-True &| False  =  _
-True &| True  =  _
-
-
-
-
-allowed deconstructions:
-
-
-Candidates for: gcd :: Int -> Int -> Int
-  pruning with 0/0 rules
-  [3,0,9,0,54,0,405,0,3402] direct candidates, 0 duplicates
-  [3,6,11,50,98,330,774,2714,6660] pattern candidates, 0 duplicates
-
-no rules.
-
-direct candidates:
-
-gcd x y  =  x
-
-gcd x y  =  y
-
-gcd x y  =  0
-
-gcd x y  =  x `mod` x
-
-gcd x y  =  x `mod` y
-
-gcd x y  =  x `mod` 0
-
-gcd x y  =  y `mod` x
-
-gcd x y  =  y `mod` y
-
-gcd x y  =  y `mod` 0
-
-gcd x y  =  0 `mod` x
-
-gcd x y  =  0 `mod` y
-
-gcd x y  =  0 `mod` 0
-
-gcd x y  =  (x `mod` x) `mod` x
-
-gcd x y  =  (x `mod` x) `mod` y
-
-gcd x y  =  (x `mod` x) `mod` 0
-
-gcd x y  =  (x `mod` y) `mod` x
-
-gcd x y  =  (x `mod` y) `mod` y
-
-gcd x y  =  (x `mod` y) `mod` 0
-
-gcd x y  =  (x `mod` 0) `mod` x
-
-gcd x y  =  (x `mod` 0) `mod` y
-
-gcd x y  =  (x `mod` 0) `mod` 0
-
-gcd x y  =  (y `mod` x) `mod` x
-
-gcd x y  =  (y `mod` x) `mod` y
-
-gcd x y  =  (y `mod` x) `mod` 0
-
-gcd x y  =  (y `mod` y) `mod` x
-
-gcd x y  =  (y `mod` y) `mod` y
-
-gcd x y  =  (y `mod` y) `mod` 0
-
-gcd x y  =  (y `mod` 0) `mod` x
-
-gcd x y  =  (y `mod` 0) `mod` y
-
-gcd x y  =  (y `mod` 0) `mod` 0
-
-gcd x y  =  (0 `mod` x) `mod` x
-
-gcd x y  =  (0 `mod` x) `mod` y
-
-gcd x y  =  (0 `mod` x) `mod` 0
-
-gcd x y  =  (0 `mod` y) `mod` x
-
-gcd x y  =  (0 `mod` y) `mod` y
-
-gcd x y  =  (0 `mod` y) `mod` 0
-
-gcd x y  =  (0 `mod` 0) `mod` x
-
-gcd x y  =  (0 `mod` 0) `mod` y
-
-gcd x y  =  (0 `mod` 0) `mod` 0
-
-gcd x y  =  x `mod` (x `mod` x)
-
-gcd x y  =  x `mod` (x `mod` y)
-
-gcd x y  =  x `mod` (x `mod` 0)
-
-gcd x y  =  x `mod` (y `mod` x)
-
-gcd x y  =  x `mod` (y `mod` y)
-
-gcd x y  =  x `mod` (y `mod` 0)
-
-gcd x y  =  x `mod` (0 `mod` x)
-
-gcd x y  =  x `mod` (0 `mod` y)
-
-gcd x y  =  x `mod` (0 `mod` 0)
-
-gcd x y  =  y `mod` (x `mod` x)
-
-gcd x y  =  y `mod` (x `mod` y)
-
-gcd x y  =  y `mod` (x `mod` 0)
-
-gcd x y  =  y `mod` (y `mod` x)
-
-gcd x y  =  y `mod` (y `mod` y)
-
-gcd x y  =  y `mod` (y `mod` 0)
-
-gcd x y  =  y `mod` (0 `mod` x)
-
-gcd x y  =  y `mod` (0 `mod` y)
-
-gcd x y  =  y `mod` (0 `mod` 0)
-
-gcd x y  =  0 `mod` (x `mod` x)
-
-gcd x y  =  0 `mod` (x `mod` y)
-
-gcd x y  =  0 `mod` (x `mod` 0)
-
-gcd x y  =  0 `mod` (y `mod` x)
-
-gcd x y  =  0 `mod` (y `mod` y)
-
-gcd x y  =  0 `mod` (y `mod` 0)
-
-gcd x y  =  0 `mod` (0 `mod` x)
-
-gcd x y  =  0 `mod` (0 `mod` y)
-
-gcd x y  =  0 `mod` (0 `mod` 0)
-
-
-pattern candidates:
-
-gcd x y  =  x
-
-gcd x y  =  y
-
-gcd x y  =  0
-
-gcd x 0  =  x
-gcd x y  =  y
-
-gcd x 0  =  x
-gcd x y  =  0
-
-gcd x 0  =  0
-gcd x y  =  x
-
-gcd 0 x  =  x
-gcd x y  =  x
-
-gcd 0 x  =  x
-gcd x y  =  0
-
-gcd 0 x  =  0
-gcd x y  =  y
-
-gcd x y  =  x `mod` x
-
-gcd x y  =  x `mod` y
-
-gcd x y  =  x `mod` 0
-
-gcd x y  =  y `mod` x
-
-gcd x y  =  y `mod` y
-
-gcd x y  =  y `mod` 0
-
-gcd x y  =  0 `mod` x
-
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  0
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  x
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  y
-
-gcd x 0  =  x
-gcd x y  =  x `mod` x
-
-gcd x 0  =  x
-gcd x y  =  x `mod` y
-
-gcd x 0  =  x
-gcd x y  =  x `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  y `mod` x
-
-gcd x 0  =  x
-gcd x y  =  y `mod` y
-
-gcd x 0  =  x
-gcd x y  =  y `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` x
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` y
-
-gcd x 0  =  0
-gcd x y  =  x `mod` x
-
-gcd x 0  =  0
-gcd x y  =  x `mod` y
-
-gcd x 0  =  0
-gcd x y  =  x `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  y `mod` x
-
-gcd x 0  =  0
-gcd x y  =  y `mod` y
-
-gcd x 0  =  0
-gcd x y  =  y `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` x
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` y
-
-gcd x 0  =  x `mod` x
-gcd x y  =  x
-
-gcd x 0  =  x `mod` x
-gcd x y  =  y
-
-gcd x 0  =  x `mod` x
-gcd x y  =  0
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  x
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  y
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  0
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  x
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  y
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  0
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  x
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  y
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  0
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  x
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  y
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  0
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  x
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  y
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  0
-
-gcd x y  =  (x `mod` x) `mod` x
-
-gcd x y  =  (x `mod` x) `mod` y
-
-gcd x y  =  (x `mod` x) `mod` 0
-
-gcd x y  =  (x `mod` y) `mod` x
-
-gcd x y  =  (x `mod` y) `mod` y
-
-gcd x y  =  (x `mod` y) `mod` 0
-
-gcd x y  =  (x `mod` 0) `mod` x
-
-gcd x y  =  (x `mod` 0) `mod` y
-
-gcd x y  =  (x `mod` 0) `mod` 0
-
-gcd x y  =  (y `mod` x) `mod` x
-
-gcd x y  =  (y `mod` x) `mod` y
-
-gcd x y  =  (y `mod` x) `mod` 0
-
-gcd x y  =  (y `mod` y) `mod` x
-
-gcd x y  =  (y `mod` y) `mod` y
-
-gcd x y  =  (y `mod` y) `mod` 0
-
-gcd x y  =  (y `mod` 0) `mod` x
-
-gcd x y  =  (y `mod` 0) `mod` y
-
-gcd x y  =  (y `mod` 0) `mod` 0
-
-gcd x y  =  (0 `mod` x) `mod` x
-
-gcd x y  =  (0 `mod` x) `mod` y
-
-gcd x y  =  (0 `mod` x) `mod` 0
-
-gcd x y  =  (0 `mod` y) `mod` x
-
-gcd x y  =  (0 `mod` y) `mod` y
-
-gcd x y  =  (0 `mod` y) `mod` 0
-
-gcd x y  =  x `mod` (x `mod` x)
-
-gcd x y  =  x `mod` (x `mod` y)
-
-gcd x y  =  x `mod` (x `mod` 0)
-
-gcd x y  =  x `mod` (y `mod` x)
-
-gcd x y  =  x `mod` (y `mod` y)
-
-gcd x y  =  x `mod` (y `mod` 0)
-
-gcd x y  =  x `mod` (0 `mod` x)
-
-gcd x y  =  x `mod` (0 `mod` y)
-
-gcd x y  =  y `mod` (x `mod` x)
-
-gcd x y  =  y `mod` (x `mod` y)
-
-gcd x y  =  y `mod` (x `mod` 0)
-
-gcd x y  =  y `mod` (y `mod` x)
-
-gcd x y  =  y `mod` (y `mod` y)
-
-gcd x y  =  y `mod` (y `mod` 0)
-
-gcd x y  =  y `mod` (0 `mod` x)
-
-gcd x y  =  y `mod` (0 `mod` y)
-
-gcd x y  =  0 `mod` (x `mod` x)
-
-gcd x y  =  0 `mod` (x `mod` y)
-
-gcd x y  =  0 `mod` (x `mod` 0)
-
-gcd x y  =  0 `mod` (y `mod` x)
-
-gcd x y  =  0 `mod` (y `mod` y)
-
-gcd x y  =  0 `mod` (y `mod` 0)
-
-gcd x y  =  0 `mod` (0 `mod` x)
-
-gcd x y  =  0 `mod` (0 `mod` y)
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  x `mod` y
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  y `mod` x
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  y `mod` y
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  y `mod` 0
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  x
-gcd x 0  =  x
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  x `mod` y
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  y `mod` x
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  y `mod` y
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  y `mod` 0
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  x
-gcd x 0  =  0
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  x
-gcd x 0  =  x `mod` x
-gcd x y  =  x
-
-gcd 0 x  =  x
-gcd x 0  =  x `mod` x
-gcd x y  =  0
-
-gcd 0 x  =  x
-gcd x 0  =  x `mod` 0
-gcd x y  =  x
-
-gcd 0 x  =  x
-gcd x 0  =  x `mod` 0
-gcd x y  =  0
-
-gcd 0 x  =  x
-gcd x 0  =  0 `mod` x
-gcd x y  =  x
-
-gcd 0 x  =  x
-gcd x 0  =  0 `mod` x
-gcd x y  =  0
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  x `mod` y
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  y `mod` x
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  y `mod` y
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  y `mod` 0
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  0
-gcd x 0  =  x
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  0
-gcd x 0  =  0
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  0
-gcd x 0  =  0
-gcd x y  =  x `mod` y
-
-gcd 0 x  =  0
-gcd x 0  =  0
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  0
-gcd x 0  =  0
-gcd x y  =  y `mod` x
-
-gcd 0 x  =  0
-gcd x 0  =  0
-gcd x y  =  y `mod` y
-
-gcd 0 x  =  0
-gcd x 0  =  0
-gcd x y  =  y `mod` 0
-
-gcd 0 x  =  0
-gcd x 0  =  0
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  0
-gcd x 0  =  0
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  0
-gcd x 0  =  x `mod` x
-gcd x y  =  y
-
-gcd 0 x  =  0
-gcd x 0  =  x `mod` 0
-gcd x y  =  y
-
-gcd 0 x  =  0
-gcd x 0  =  0 `mod` x
-gcd x y  =  y
-
-gcd 0 x  =  x `mod` x
-gcd x 0  =  x
-gcd x y  =  y
-
-gcd 0 x  =  x `mod` x
-gcd x 0  =  x
-gcd x y  =  0
-
-gcd 0 x  =  x `mod` x
-gcd x 0  =  0
-gcd x y  =  x
-
-gcd 0 x  =  x `mod` 0
-gcd x 0  =  x
-gcd x y  =  y
-
-gcd 0 x  =  x `mod` 0
-gcd x 0  =  x
-gcd x y  =  0
-
-gcd 0 x  =  x `mod` 0
-gcd x 0  =  0
-gcd x y  =  x
-
-gcd 0 x  =  0 `mod` x
-gcd x 0  =  x
-gcd x y  =  y
-
-gcd 0 x  =  0 `mod` x
-gcd x 0  =  x
-gcd x y  =  0
-
-gcd 0 x  =  0 `mod` x
-gcd x 0  =  0
-gcd x y  =  x
-
-gcd x 0  =  x
-gcd x y  =  gcd x (x `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  gcd x (y `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  gcd y (x `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  gcd y (x `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  gcd y (y `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  gcd y (y `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  gcd 0 (x `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  gcd 0 (y `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  gcd (x `mod` x) x
-
-gcd x 0  =  x
-gcd x y  =  gcd (x `mod` x) y
-
-gcd x 0  =  x
-gcd x y  =  gcd (x `mod` y) x
-
-gcd x 0  =  x
-gcd x y  =  gcd (y `mod` x) x
-
-gcd x 0  =  x
-gcd x y  =  gcd (y `mod` x) y
-
-gcd x 0  =  x
-gcd x y  =  gcd (y `mod` y) x
-
-gcd 0 x  =  x
-gcd x y  =  gcd x (x `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  gcd x (y `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  gcd y (x `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  gcd y (x `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  gcd y (y `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  gcd y (y `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  gcd (x `mod` x) x
-
-gcd 0 x  =  x
-gcd x y  =  gcd (x `mod` x) y
-
-gcd 0 x  =  x
-gcd x y  =  gcd (x `mod` x) 0
-
-gcd 0 x  =  x
-gcd x y  =  gcd (x `mod` y) x
-
-gcd 0 x  =  x
-gcd x y  =  gcd (y `mod` x) x
-
-gcd 0 x  =  x
-gcd x y  =  gcd (y `mod` x) y
-
-gcd 0 x  =  x
-gcd x y  =  gcd (y `mod` x) 0
-
-gcd 0 x  =  x
-gcd x y  =  gcd (y `mod` y) x
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` x) `mod` x
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` x) `mod` y
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` x) `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` y) `mod` x
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` y) `mod` y
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` y) `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` 0) `mod` x
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` 0) `mod` y
-
-gcd x 0  =  x
-gcd x y  =  (x `mod` 0) `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` x) `mod` x
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` x) `mod` y
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` x) `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` y) `mod` x
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` y) `mod` y
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` y) `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` 0) `mod` x
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` 0) `mod` y
-
-gcd x 0  =  x
-gcd x y  =  (y `mod` 0) `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  (0 `mod` x) `mod` x
-
-gcd x 0  =  x
-gcd x y  =  (0 `mod` x) `mod` y
-
-gcd x 0  =  x
-gcd x y  =  (0 `mod` x) `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  (0 `mod` y) `mod` x
-
-gcd x 0  =  x
-gcd x y  =  (0 `mod` y) `mod` y
-
-gcd x 0  =  x
-gcd x y  =  (0 `mod` y) `mod` 0
-
-gcd x 0  =  x
-gcd x y  =  x `mod` (x `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  x `mod` (x `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  x `mod` (x `mod` 0)
-
-gcd x 0  =  x
-gcd x y  =  x `mod` (y `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  x `mod` (y `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  x `mod` (y `mod` 0)
-
-gcd x 0  =  x
-gcd x y  =  x `mod` (0 `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  x `mod` (0 `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  y `mod` (x `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  y `mod` (x `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  y `mod` (x `mod` 0)
-
-gcd x 0  =  x
-gcd x y  =  y `mod` (y `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  y `mod` (y `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  y `mod` (y `mod` 0)
-
-gcd x 0  =  x
-gcd x y  =  y `mod` (0 `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  y `mod` (0 `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` (x `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` (x `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` (x `mod` 0)
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` (y `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` (y `mod` y)
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` (y `mod` 0)
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` (0 `mod` x)
-
-gcd x 0  =  x
-gcd x y  =  0 `mod` (0 `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` x) `mod` x
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` x) `mod` y
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` x) `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` y) `mod` x
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` y) `mod` y
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` y) `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` 0) `mod` x
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` 0) `mod` y
-
-gcd x 0  =  0
-gcd x y  =  (x `mod` 0) `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` x) `mod` x
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` x) `mod` y
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` x) `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` y) `mod` x
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` y) `mod` y
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` y) `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` 0) `mod` x
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` 0) `mod` y
-
-gcd x 0  =  0
-gcd x y  =  (y `mod` 0) `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  (0 `mod` x) `mod` x
-
-gcd x 0  =  0
-gcd x y  =  (0 `mod` x) `mod` y
-
-gcd x 0  =  0
-gcd x y  =  (0 `mod` x) `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  (0 `mod` y) `mod` x
-
-gcd x 0  =  0
-gcd x y  =  (0 `mod` y) `mod` y
-
-gcd x 0  =  0
-gcd x y  =  (0 `mod` y) `mod` 0
-
-gcd x 0  =  0
-gcd x y  =  x `mod` (x `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  x `mod` (x `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  x `mod` (x `mod` 0)
-
-gcd x 0  =  0
-gcd x y  =  x `mod` (y `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  x `mod` (y `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  x `mod` (y `mod` 0)
-
-gcd x 0  =  0
-gcd x y  =  x `mod` (0 `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  x `mod` (0 `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  y `mod` (x `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  y `mod` (x `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  y `mod` (x `mod` 0)
-
-gcd x 0  =  0
-gcd x y  =  y `mod` (y `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  y `mod` (y `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  y `mod` (y `mod` 0)
-
-gcd x 0  =  0
-gcd x y  =  y `mod` (0 `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  y `mod` (0 `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` (x `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` (x `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` (x `mod` 0)
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` (y `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` (y `mod` y)
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` (y `mod` 0)
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` (0 `mod` x)
-
-gcd x 0  =  0
-gcd x y  =  0 `mod` (0 `mod` y)
-
-gcd x 0  =  x `mod` x
-gcd x y  =  x `mod` y
-
-gcd x 0  =  x `mod` x
-gcd x y  =  x `mod` 0
-
-gcd x 0  =  x `mod` x
-gcd x y  =  y `mod` x
-
-gcd x 0  =  x `mod` x
-gcd x y  =  y `mod` y
-
-gcd x 0  =  x `mod` x
-gcd x y  =  y `mod` 0
-
-gcd x 0  =  x `mod` x
-gcd x y  =  0 `mod` x
-
-gcd x 0  =  x `mod` x
-gcd x y  =  0 `mod` y
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  x `mod` x
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  y `mod` x
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  y `mod` y
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  y `mod` 0
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  0 `mod` x
-
-gcd x 0  =  x `mod` 0
-gcd x y  =  0 `mod` y
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  x `mod` x
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  x `mod` y
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  x `mod` 0
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  y `mod` y
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  y `mod` 0
-
-gcd x 0  =  0 `mod` x
-gcd x y  =  0 `mod` y
-
-gcd x 0  =  (x `mod` x) `mod` x
-gcd x y  =  x
-
-gcd x 0  =  (x `mod` x) `mod` x
-gcd x y  =  y
-
-gcd x 0  =  (x `mod` x) `mod` x
-gcd x y  =  0
-
-gcd x 0  =  (x `mod` x) `mod` 0
-gcd x y  =  x
-
-gcd x 0  =  (x `mod` x) `mod` 0
-gcd x y  =  y
-
-gcd x 0  =  (x `mod` x) `mod` 0
-gcd x y  =  0
-
-gcd x 0  =  (x `mod` 0) `mod` x
-gcd x y  =  x
-
-gcd x 0  =  (x `mod` 0) `mod` x
-gcd x y  =  y
-
-gcd x 0  =  (x `mod` 0) `mod` x
-gcd x y  =  0
-
-gcd x 0  =  (x `mod` 0) `mod` 0
-gcd x y  =  x
-
-gcd x 0  =  (x `mod` 0) `mod` 0
-gcd x y  =  y
-
-gcd x 0  =  (x `mod` 0) `mod` 0
-gcd x y  =  0
-
-gcd x 0  =  (0 `mod` x) `mod` x
-gcd x y  =  x
-
-gcd x 0  =  (0 `mod` x) `mod` x
-gcd x y  =  y
-
-gcd x 0  =  (0 `mod` x) `mod` x
-gcd x y  =  0
-
-gcd x 0  =  (0 `mod` x) `mod` 0
-gcd x y  =  x
-
-gcd x 0  =  (0 `mod` x) `mod` 0
-gcd x y  =  y
-
-gcd x 0  =  (0 `mod` x) `mod` 0
-gcd x y  =  0
-
-gcd x 0  =  x `mod` (x `mod` x)
-gcd x y  =  x
-
-gcd x 0  =  x `mod` (x `mod` x)
-gcd x y  =  y
-
-gcd x 0  =  x `mod` (x `mod` x)
-gcd x y  =  0
-
-gcd x 0  =  x `mod` (x `mod` 0)
-gcd x y  =  x
-
-gcd x 0  =  x `mod` (x `mod` 0)
-gcd x y  =  y
-
-gcd x 0  =  x `mod` (x `mod` 0)
-gcd x y  =  0
-
-gcd x 0  =  x `mod` (0 `mod` x)
-gcd x y  =  x
-
-gcd x 0  =  x `mod` (0 `mod` x)
-gcd x y  =  y
-
-gcd x 0  =  x `mod` (0 `mod` x)
-gcd x y  =  0
-
-gcd x 0  =  0 `mod` (x `mod` x)
-gcd x y  =  x
-
-gcd x 0  =  0 `mod` (x `mod` x)
-gcd x y  =  y
-
-gcd x 0  =  0 `mod` (x `mod` x)
-gcd x y  =  0
-
-gcd x 0  =  0 `mod` (x `mod` 0)
-gcd x y  =  x
-
-gcd x 0  =  0 `mod` (x `mod` 0)
-gcd x y  =  y
-
-gcd x 0  =  0 `mod` (x `mod` 0)
-gcd x y  =  0
-
-gcd x 0  =  0 `mod` (0 `mod` x)
-gcd x y  =  x
-
-gcd x 0  =  0 `mod` (0 `mod` x)
-gcd x y  =  y
-
-gcd x 0  =  0 `mod` (0 `mod` x)
-gcd x y  =  0
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` x) `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` x) `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` x) `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` y) `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` y) `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` y) `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` 0) `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` 0) `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  (x `mod` 0) `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` x) `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` x) `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` x) `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` y) `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` y) `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` y) `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` 0) `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` 0) `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  (y `mod` 0) `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  (0 `mod` x) `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  (0 `mod` x) `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  (0 `mod` x) `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  (0 `mod` y) `mod` x
-
-gcd 0 x  =  x
-gcd x y  =  (0 `mod` y) `mod` y
-
-gcd 0 x  =  x
-gcd x y  =  (0 `mod` y) `mod` 0
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` (x `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` (x `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` (x `mod` 0)
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` (y `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` (y `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` (y `mod` 0)
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` (0 `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  x `mod` (0 `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` (x `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` (x `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` (x `mod` 0)
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` (y `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` (y `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` (y `mod` 0)
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` (0 `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  y `mod` (0 `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` (x `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` (x `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` (x `mod` 0)
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` (y `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` (y `mod` y)
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` (y `mod` 0)
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` (0 `mod` x)
-
-gcd 0 x  =  x
-gcd x y  =  0 `mod` (0 `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` x) `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` x) `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` x) `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` y) `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` y) `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` y) `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` 0) `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` 0) `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  (x `mod` 0) `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` x) `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` x) `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` x) `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` y) `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` y) `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` y) `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` 0) `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` 0) `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  (y `mod` 0) `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  (0 `mod` x) `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  (0 `mod` x) `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  (0 `mod` x) `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  (0 `mod` y) `mod` x
-
-gcd 0 x  =  0
-gcd x y  =  (0 `mod` y) `mod` y
-
-gcd 0 x  =  0
-gcd x y  =  (0 `mod` y) `mod` 0
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` (x `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` (x `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` (x `mod` 0)
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` (y `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` (y `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` (y `mod` 0)
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` (0 `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  x `mod` (0 `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` (x `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` (x `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` (x `mod` 0)
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` (y `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` (y `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` (y `mod` 0)
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` (0 `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  y `mod` (0 `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` (x `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` (x `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` (x `mod` 0)
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` (y `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` (y `mod` y)
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` (y `mod` 0)
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` (0 `mod` x)
-
-gcd 0 x  =  0
-gcd x y  =  0 `mod` (0 `mod` y)
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  x `mod` y
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  y `mod` x
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  y `mod` 0
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  x `mod` x
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  x `mod` y
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  y `mod` y
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  x `mod` 0
-gcd x y  =  0 `mod` y
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  x `mod` x
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  x `mod` 0
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  y `mod` x
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  y `mod` y
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  y `mod` 0
-
-gcd 0 x  =  0 `mod` x
-gcd x y  =  0 `mod` x
-
-gcd 0 x  =  (x `mod` x) `mod` x
-gcd x y  =  x
-
-gcd 0 x  =  (x `mod` x) `mod` x
-gcd x y  =  y
-
-gcd 0 x  =  (x `mod` x) `mod` x
-gcd x y  =  0
-
-gcd 0 x  =  (x `mod` x) `mod` 0
-gcd x y  =  x
-
-gcd 0 x  =  (x `mod` x) `mod` 0
-gcd x y  =  y
-
-gcd 0 x  =  (x `mod` x) `mod` 0
-gcd x y  =  0
-
-gcd 0 x  =  (x `mod` 0) `mod` x
-gcd x y  =  x
-
-gcd 0 x  =  (x `mod` 0) `mod` x
-gcd x y  =  y
-
-gcd 0 x  =  (x `mod` 0) `mod` x
-gcd x y  =  0
-
-gcd 0 x  =  (x `mod` 0) `mod` 0
-gcd x y  =  x
-
-gcd 0 x  =  (x `mod` 0) `mod` 0
-gcd x y  =  y
-
-gcd 0 x  =  (x `mod` 0) `mod` 0
-gcd x y  =  0
-
-gcd 0 x  =  (0 `mod` x) `mod` x
-gcd x y  =  x
-
-gcd 0 x  =  (0 `mod` x) `mod` x
-gcd x y  =  y
-
-gcd 0 x  =  (0 `mod` x) `mod` x
-gcd x y  =  0
-
-gcd 0 x  =  (0 `mod` x) `mod` 0
-gcd x y  =  x
-
-gcd 0 x  =  (0 `mod` x) `mod` 0
-gcd x y  =  y
-
-gcd 0 x  =  (0 `mod` x) `mod` 0
-gcd x y  =  0
-
-gcd 0 x  =  x `mod` (x `mod` x)
-gcd x y  =  x
-
-gcd 0 x  =  x `mod` (x `mod` x)
-gcd x y  =  y
-
-gcd 0 x  =  x `mod` (x `mod` x)
-gcd x y  =  0
-
-gcd 0 x  =  x `mod` (x `mod` 0)
-gcd x y  =  x
-
-gcd 0 x  =  x `mod` (x `mod` 0)
-gcd x y  =  y
-
-gcd 0 x  =  x `mod` (x `mod` 0)
-gcd x y  =  0
-
-gcd 0 x  =  x `mod` (0 `mod` x)
-gcd x y  =  x
-
-gcd 0 x  =  x `mod` (0 `mod` x)
-gcd x y  =  y
-
-gcd 0 x  =  x `mod` (0 `mod` x)
-gcd x y  =  0
-
-gcd 0 x  =  0 `mod` (x `mod` x)
-gcd x y  =  x
-
-gcd 0 x  =  0 `mod` (x `mod` x)
-gcd x y  =  y
-
-gcd 0 x  =  0 `mod` (x `mod` x)
-gcd x y  =  0
-
-gcd 0 x  =  0 `mod` (x `mod` 0)
-gcd x y  =  x
-
-gcd 0 x  =  0 `mod` (x `mod` 0)
-gcd x y  =  y
-
-gcd 0 x  =  0 `mod` (x `mod` 0)
-gcd x y  =  0
-
-gcd 0 x  =  0 `mod` (0 `mod` x)
-gcd x y  =  x
-
-gcd 0 x  =  0 `mod` (0 `mod` x)
-gcd x y  =  y
-
-gcd 0 x  =  0 `mod` (0 `mod` x)
-gcd x y  =  0
+foo x  =  x + (x + x)
+
+foo x  =  x + (x + 1)
+
+foo x  =  x + (1 + 1)
+
+foo x  =  x + x * x
+
+foo x  =  x + (x - 1)
+
+foo x  =  x + (0 - 1)
+
+foo x  =  1 + (x + x)
+
+foo x  =  1 + (x + 1)
+
+foo x  =  1 + (1 + 1)
+
+foo x  =  1 + x * x
+
+foo x  =  1 + (0 - x)
+
+foo x  =  1 + (1 - x)
+
+foo x  =  x * (x + x)
+
+foo x  =  x * (x * x)
+
+foo x  =  x * (x - 1)
+
+foo x  =  x * (0 - x)
+
+foo x  =  x * (0 - 1)
+
+foo x  =  x * (1 - x)
+
+foo x  =  x - (x + x)
+
+foo x  =  x - (x + 1)
+
+foo x  =  x - (1 + 1)
+
+foo x  =  x - x * x
+
+foo x  =  0 - (x + x)
+
+foo x  =  0 - (x + 1)
+
+foo x  =  0 - (1 + 1)
+
+foo x  =  1 - (x + x)
+
+foo x  =  1 - (x + 1)
+
+foo x  =  1 - (1 + 1)
+
+foo x  =  1 - x * x
+
+foo x  =  x * x - 1
+
+
+pattern candidates:
+
+foo x  =  x
+
+foo x  =  0
+
+foo x  =  1
+
+foo 0  =  0
+foo x  =  1
+
+foo 0  =  1
+foo x  =  x
+
+foo 0  =  1
+foo x  =  0
+
+foo x  =  x + x
+
+foo x  =  x + 1
+
+foo x  =  x * x
+
+foo x  =  x - 1
+
+foo x  =  0 - x
+
+foo x  =  1 - x
+
+foo 1  =  0
+foo x  =  x
+
+foo 1  =  0
+foo x  =  1
+
+foo 1  =  1
+foo x  =  0
+
+foo 0  =  0
+foo x  =  x + 1
+
+foo 0  =  0
+foo x  =  x - 1
+
+foo 0  =  0
+foo x  =  1 - x
+
+foo 0  =  1
+foo x  =  x + x
+
+foo 0  =  1
+foo x  =  x * x
+
+foo 0  =  1
+foo x  =  x - 1
+
+foo 0  =  1
+foo x  =  0 - x
+
+foo 0  =  0
+foo 1  =  0
+foo x  =  1
+
+foo 0  =  1
+foo 1  =  0
+foo x  =  x
+
+foo 0  =  1
+foo 1  =  1
+foo x  =  0
+
+foo x  =  x + (x + x)
+
+foo x  =  x + (x + 1)
+
+foo x  =  x + x * x
+
+foo x  =  x + (x - 1)
+
+foo x  =  1 + (x + x)
+
+foo x  =  1 + (x + 1)
+
+foo x  =  1 + x * x
+
+foo x  =  1 + (0 - x)
+
+foo x  =  1 + (1 - x)
+
+foo x  =  x * (x + x)
+
+foo x  =  x * (x * x)
+
+foo x  =  x * (x - 1)
+
+foo x  =  x * (0 - x)
+
+foo x  =  x * (1 - x)
+
+foo x  =  x - (x + x)
+
+foo x  =  x - (x + 1)
+
+foo x  =  x - x * x
+
+foo x  =  0 - (x + x)
+
+foo x  =  0 - (x + 1)
+
+foo x  =  1 - (x + x)
+
+foo x  =  1 - (x + 1)
+
+foo x  =  1 - x * x
+
+foo x  =  x * x - 1
+
+foo 1  =  0
+foo x  =  x + x
+
+foo 1  =  0
+foo x  =  x + 1
+
+foo 1  =  0
+foo x  =  x * x
+
+foo 1  =  0
+foo x  =  0 - x
+
+foo 1  =  1
+foo x  =  x + x
+
+foo 1  =  1
+foo x  =  x + 1
+
+foo 1  =  1
+foo x  =  x - 1
+
+foo 1  =  1
+foo x  =  0 - x
+
+foo 1  =  1
+foo x  =  1 - x
+
+foo 0  =  0
+foo x  =  x + (x + 1)
+
+foo 0  =  0
+foo x  =  x + (x - 1)
+
+foo 0  =  0
+foo x  =  1 + (x + x)
+
+foo 0  =  0
+foo x  =  1 + (x + 1)
+
+foo 0  =  0
+foo x  =  1 + x * x
+
+foo 0  =  0
+foo x  =  1 + (0 - x)
+
+foo 0  =  0
+foo x  =  1 + (1 - x)
+
+foo 0  =  0
+foo x  =  x - (x + 1)
+
+foo 0  =  0
+foo x  =  0 - (x + 1)
+
+foo 0  =  0
+foo x  =  1 - (x + x)
+
+foo 0  =  0
+foo x  =  1 - x * x
+
+foo 0  =  0
+foo x  =  x * x - 1
+
+foo 0  =  1
+foo x  =  x + (x + x)
+
+foo 0  =  1
+foo x  =  x + x * x
+
+foo 0  =  1
+foo x  =  x + (x - 1)
+
+foo 0  =  1
+foo x  =  1 + (x + 1)
+
+foo 0  =  1
+foo x  =  1 + (1 - x)
+
+foo 0  =  1
+foo x  =  x * (x + x)
+
+foo 0  =  1
+foo x  =  x * (x * x)
+
+foo 0  =  1
+foo x  =  x * (x - 1)
+
+foo 0  =  1
+foo x  =  x * (0 - x)
+
+foo 0  =  1
+foo x  =  x * (1 - x)
+
+foo 0  =  1
+foo x  =  x - (x + x)
+
+foo 0  =  1
+foo x  =  x - (x + 1)
+
+foo 0  =  1
+foo x  =  x - x * x
+
+foo 0  =  1
+foo x  =  0 - (x + x)
+
+foo 0  =  1
+foo x  =  0 - (x + 1)
+
+foo 0  =  1
+foo x  =  1 - (x + 1)
+
+foo 0  =  1
+foo x  =  x * x - 1
+
+foo 0  =  0
+foo 1  =  0
+foo x  =  x + 1
+
+foo 0  =  0
+foo 1  =  1
+foo x  =  x + 1
+
+foo 0  =  0
+foo 1  =  1
+foo x  =  x - 1
+
+foo 0  =  0
+foo 1  =  1
+foo x  =  1 - x
+
+foo 0  =  1
+foo 1  =  0
+foo x  =  x + x
+
+foo 0  =  1
+foo 1  =  0
+foo x  =  x * x
+
+foo 0  =  1
+foo 1  =  0
+foo x  =  0 - x
+
+foo 0  =  1
+foo 1  =  1
+foo x  =  x + x
+
+foo 0  =  1
+foo 1  =  1
+foo x  =  x - 1
+
+foo 0  =  1
+foo 1  =  1
+foo x  =  0 - x
+
+
+
+allowed patterns:
+
+foo x  =  _
+
+
+foo 0  =  _
+foo x  =  _
+
+
+foo 1  =  _
+foo x  =  _
+
+
+foo 0  =  _
+foo 1  =  _
+foo x  =  _
+
+
+
+
+allowed deconstructions:
+
+_ - 1 :: Int
+
+Candidates for: ? :: Int -> Int -> Int
+  pruning with 13/34 rules
+  [3,3,9,18,60,162,489,1475,4619] direct candidates, 0 duplicates
+  [3,8,25,71,205,632,1957,5906,18303] pattern candidates, 0 duplicates
+
+rules:
+x * 0 == 0
+0 * x == 0
+x + 0 == x
+0 + x == x
+dec (x + y) == x + dec y
+dec (x + y) == y + dec x
+dec (x + y) == dec x + y
+dec (x + y) == dec y + x
+(x * y) * z == x * (y * z)
+(x * y) * z == y * (x * z)
+(x + y) + z == x + (y + z)
+(x + y) + z == y + (x + z)
+(x + x) * y == x * (y + y)
+equations:
+y * x == x * y
+y + x == x + y
+y + dec x == x + dec y
+dec x + y == x + dec y
+dec y + x == dec x + y
+x + dec 0 == dec x
+dec 0 + x == dec x
+y * (x * z) == x * (y * z)
+z * (x * y) == x * (y * z)
+z * (y * x) == x * (y * z)
+y + (x + z) == x + (y + z)
+z + (x + y) == x + (y + z)
+z + (y + x) == x + (y + z)
+(z + y) * x == x * (y + z)
+z * y + x == x + y * z
+y * (x + x) == x * (y + y)
+y + dec (dec x) == x + dec (dec y)
+dec (dec x) + y == x + dec (dec y)
+dec (dec y) + x == dec (dec x) + y
+x + dec (dec 0) == dec (dec x)
+dec (dec 0) + x == dec (dec x)
+
+direct candidates:
+
+x ? y  =  x
+
+x ? y  =  y
+
+x ? y  =  0
+
+x ? y  =  dec x
+
+x ? y  =  dec y
+
+x ? y  =  dec 0
+
+x ? y  =  dec (dec x)
+
+x ? y  =  dec (dec y)
+
+x ? y  =  dec (dec 0)
+
+x ? y  =  x + x
+
+x ? y  =  x + y
+
+x ? y  =  y + y
+
+x ? y  =  x * x
+
+x ? y  =  x * y
+
+x ? y  =  y * y
+
+x ? y  =  dec (dec (dec x))
+
+x ? y  =  dec (dec (dec y))
+
+x ? y  =  dec (dec (dec 0))
+
+x ? y  =  dec (x * x)
+
+x ? y  =  dec (x * y)
+
+x ? y  =  dec (y * y)
+
+x ? y  =  x + dec x
+
+x ? y  =  x + dec y
+
+x ? y  =  x + dec 0
+
+x ? y  =  y + dec x
+
+x ? y  =  y + dec y
+
+x ? y  =  y + dec 0
+
+x ? y  =  x * dec x
+
+x ? y  =  x * dec y
+
+x ? y  =  x * dec 0
+
+x ? y  =  y * dec x
+
+x ? y  =  y * dec y
+
+x ? y  =  y * dec 0
+
+x ? y  =  dec (dec (dec (dec x)))
+
+x ? y  =  dec (dec (dec (dec y)))
+
+x ? y  =  dec (dec (dec (dec 0)))
+
+x ? y  =  dec (dec (x * x))
+
+x ? y  =  dec (dec (x * y))
+
+x ? y  =  dec (dec (y * y))
+
+x ? y  =  dec (x * dec x)
+
+x ? y  =  dec (x * dec y)
+
+x ? y  =  dec (x * dec 0)
+
+x ? y  =  dec (y * dec x)
+
+x ? y  =  dec (y * dec y)
+
+x ? y  =  dec (y * dec 0)
+
+x ? y  =  x + dec (dec x)
+
+x ? y  =  x + dec (dec y)
+
+x ? y  =  x + dec (dec 0)
+
+x ? y  =  x + (x + x)
+
+x ? y  =  x + (x + y)
+
+x ? y  =  x + (y + y)
+
+x ? y  =  x + x * x
+
+x ? y  =  x + x * y
+
+x ? y  =  x + y * y
+
+x ? y  =  y + dec (dec x)
+
+x ? y  =  y + dec (dec y)
+
+x ? y  =  y + dec (dec 0)
+
+x ? y  =  y + (x + x)
+
+x ? y  =  y + (x + y)
+
+x ? y  =  y + (y + y)
+
+x ? y  =  y + x * x
+
+x ? y  =  y + x * y
+
+x ? y  =  y + y * y
+
+x ? y  =  x * dec (dec x)
+
+x ? y  =  x * dec (dec y)
+
+x ? y  =  x * dec (dec 0)
+
+x ? y  =  x * (x + x)
+
+x ? y  =  x * (x + y)
+
+x ? y  =  x * (y + y)
+
+x ? y  =  x * (x * x)
+
+x ? y  =  x * (x * y)
+
+x ? y  =  x * (y * y)
+
+x ? y  =  y * dec (dec x)
+
+x ? y  =  y * dec (dec y)
+
+x ? y  =  y * dec (dec 0)
+
+x ? y  =  y * (x + x)
+
+x ? y  =  y * (x + y)
+
+x ? y  =  y * (y + y)
+
+x ? y  =  y * (x * x)
+
+x ? y  =  y * (x * y)
+
+x ? y  =  y * (y * y)
+
+x ? y  =  dec x + dec x
+
+x ? y  =  dec x + dec y
+
+x ? y  =  dec x + dec 0
+
+x ? y  =  dec y + dec y
+
+x ? y  =  dec y + dec 0
+
+x ? y  =  dec 0 + dec 0
+
+x ? y  =  dec x * dec x
+
+x ? y  =  dec x * dec y
+
+x ? y  =  dec x * dec 0
+
+x ? y  =  dec y * dec y
+
+x ? y  =  dec y * dec 0
+
+x ? y  =  dec 0 * dec 0
+
+
+pattern candidates:
+
+x ? y  =  x
+
+x ? y  =  y
+
+x ? y  =  0
+
+x ? y  =  dec x
+
+x ? y  =  dec y
+
+x ? 0  =  x
+x ? y  =  y
+
+x ? 0  =  x
+x ? y  =  0
+
+x ? 0  =  0
+x ? y  =  x
+
+0 ? x  =  x
+x ? y  =  x
+
+0 ? x  =  x
+x ? y  =  0
+
+0 ? x  =  0
+x ? y  =  y
+
+x ? y  =  dec (dec x)
+
+x ? y  =  dec (dec y)
+
+x ? y  =  x + x
+
+x ? y  =  x + y
+
+x ? y  =  y + y
+
+x ? y  =  x * x
+
+x ? y  =  x * y
+
+x ? y  =  y * y
+
+x ? 0  =  x
+x ? y  =  dec x
+
+x ? 0  =  x
+x ? y  =  dec y
+
+x ? 0  =  0
+x ? y  =  dec x
+
+x ? 0  =  0
+x ? y  =  dec y
+
+x ? 0  =  dec x
+x ? y  =  x
+
+x ? 0  =  dec x
+x ? y  =  y
+
+x ? 0  =  dec x
+x ? y  =  0
+
+0 ? x  =  x
+x ? y  =  dec x
+
+0 ? x  =  x
+x ? y  =  dec y
+
+0 ? x  =  0
+x ? y  =  dec x
+
+0 ? x  =  0
+x ? y  =  dec y
+
+0 ? x  =  dec x
+x ? y  =  x
+
+0 ? x  =  dec x
+x ? y  =  y
+
+0 ? x  =  dec x
+x ? y  =  0
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  0
+
+0 ? x  =  x
+x ? 0  =  0
+x ? y  =  x
+
+0 ? x  =  0
+x ? 0  =  x
+x ? y  =  y
+
+x ? y  =  dec (dec (dec x))
+
+x ? y  =  dec (dec (dec y))
+
+x ? y  =  dec (x * x)
+
+x ? y  =  dec (x * y)
+
+x ? y  =  dec (y * y)
+
+x ? y  =  x + dec x
+
+x ? y  =  x + dec y
+
+x ? y  =  y + dec x
+
+x ? y  =  y + dec y
+
+x ? y  =  x * dec x
+
+x ? y  =  x * dec y
+
+x ? y  =  y * dec x
+
+x ? y  =  y * dec y
+
+x ? 0  =  x
+x ? y  =  dec (dec x)
+
+x ? 0  =  x
+x ? y  =  dec (dec y)
+
+x ? 0  =  x
+x ? y  =  x + x
+
+x ? 0  =  x
+x ? y  =  y + y
+
+x ? 0  =  x
+x ? y  =  x * x
+
+x ? 0  =  x
+x ? y  =  x * y
+
+x ? 0  =  x
+x ? y  =  y * y
+
+x ? 0  =  0
+x ? y  =  dec (dec x)
+
+x ? 0  =  0
+x ? y  =  dec (dec y)
+
+x ? 0  =  0
+x ? y  =  x + x
+
+x ? 0  =  0
+x ? y  =  x + y
+
+x ? 0  =  0
+x ? y  =  x * x
+
+x ? 0  =  dec x
+x ? y  =  dec y
+
+x ? 0  =  dec (dec x)
+x ? y  =  x
+
+x ? 0  =  dec (dec x)
+x ? y  =  y
+
+x ? 0  =  dec (dec x)
+x ? y  =  0
+
+x ? 0  =  x + x
+x ? y  =  x
+
+x ? 0  =  x + x
+x ? y  =  y
+
+x ? 0  =  x + x
+x ? y  =  0
+
+x ? 0  =  x * x
+x ? y  =  x
+
+x ? 0  =  x * x
+x ? y  =  y
+
+x ? 0  =  x * x
+x ? y  =  0
+
+0 ? x  =  x
+x ? y  =  dec (dec x)
+
+0 ? x  =  x
+x ? y  =  dec (dec y)
+
+0 ? x  =  x
+x ? y  =  x + x
+
+0 ? x  =  x
+x ? y  =  y + y
+
+0 ? x  =  x
+x ? y  =  x * x
+
+0 ? x  =  x
+x ? y  =  x * y
+
+0 ? x  =  x
+x ? y  =  y * y
+
+0 ? x  =  0
+x ? y  =  dec (dec x)
+
+0 ? x  =  0
+x ? y  =  dec (dec y)
+
+0 ? x  =  0
+x ? y  =  x + y
+
+0 ? x  =  0
+x ? y  =  y + y
+
+0 ? x  =  0
+x ? y  =  y * y
+
+0 ? x  =  dec x
+x ? y  =  dec x
+
+0 ? x  =  dec (dec x)
+x ? y  =  x
+
+0 ? x  =  dec (dec x)
+x ? y  =  y
+
+0 ? x  =  dec (dec x)
+x ? y  =  0
+
+0 ? x  =  x + x
+x ? y  =  x
+
+0 ? x  =  x + x
+x ? y  =  y
+
+0 ? x  =  x + x
+x ? y  =  0
+
+0 ? x  =  x * x
+x ? y  =  x
+
+0 ? x  =  x * x
+x ? y  =  y
+
+0 ? x  =  x * x
+x ? y  =  0
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  dec x
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  dec y
+
+0 ? x  =  x
+x ? 0  =  0
+x ? y  =  dec x
+
+0 ? x  =  x
+x ? 0  =  0
+x ? y  =  dec y
+
+0 ? x  =  x
+x ? 0  =  dec x
+x ? y  =  x
+
+0 ? x  =  x
+x ? 0  =  dec x
+x ? y  =  0
+
+0 ? x  =  0
+x ? 0  =  x
+x ? y  =  dec x
+
+0 ? x  =  0
+x ? 0  =  x
+x ? y  =  dec y
+
+0 ? x  =  0
+x ? 0  =  0
+x ? y  =  dec x
+
+0 ? x  =  0
+x ? 0  =  0
+x ? y  =  dec y
+
+0 ? x  =  0
+x ? 0  =  dec x
+x ? y  =  y
+
+0 ? x  =  dec x
+x ? 0  =  x
+x ? y  =  y
+
+0 ? x  =  dec x
+x ? 0  =  x
+x ? y  =  0
+
+0 ? x  =  dec x
+x ? 0  =  0
+x ? y  =  x
+
+x ? y  =  dec (dec (dec (dec x)))
+
+x ? y  =  dec (dec (dec (dec y)))
+
+x ? y  =  dec (dec (x * x))
+
+x ? y  =  dec (dec (x * y))
+
+x ? y  =  dec (dec (y * y))
+
+x ? y  =  dec (x * dec x)
+
+x ? y  =  dec (x * dec y)
+
+x ? y  =  dec (y * dec x)
+
+x ? y  =  dec (y * dec y)
+
+x ? y  =  x + dec (dec x)
+
+x ? y  =  x + dec (dec y)
+
+x ? y  =  x + (x + x)
+
+x ? y  =  x + (x + y)
+
+x ? y  =  x + (y + y)
+
+x ? y  =  x + x * x
+
+x ? y  =  x + x * y
+
+x ? y  =  x + y * y
+
+x ? y  =  y + dec (dec x)
+
+x ? y  =  y + dec (dec y)
+
+x ? y  =  y + (x + x)
+
+x ? y  =  y + (x + y)
+
+x ? y  =  y + (y + y)
+
+x ? y  =  y + x * x
+
+x ? y  =  y + x * y
+
+x ? y  =  y + y * y
+
+x ? y  =  x * dec (dec x)
+
+x ? y  =  x * dec (dec y)
+
+x ? y  =  x * (x + x)
+
+x ? y  =  x * (x + y)
+
+x ? y  =  x * (y + y)
+
+x ? y  =  x * (x * x)
+
+x ? y  =  x * (x * y)
+
+x ? y  =  x * (y * y)
+
+x ? y  =  y * dec (dec x)
+
+x ? y  =  y * dec (dec y)
+
+x ? y  =  y * (x + x)
+
+x ? y  =  y * (x + y)
+
+x ? y  =  y * (y + y)
+
+x ? y  =  y * (x * x)
+
+x ? y  =  y * (x * y)
+
+x ? y  =  y * (y * y)
+
+x ? y  =  dec x + dec x
+
+x ? y  =  dec x + dec y
+
+x ? y  =  dec y + dec y
+
+x ? y  =  dec x * dec x
+
+x ? y  =  dec x * dec y
+
+x ? y  =  dec y * dec y
+
+x ? 0  =  x
+x ? y  =  dec (dec (dec x))
+
+x ? 0  =  x
+x ? y  =  dec (dec (dec y))
+
+x ? 0  =  x
+x ? y  =  dec (x * x)
+
+x ? 0  =  x
+x ? y  =  dec (x * y)
+
+x ? 0  =  x
+x ? y  =  dec (y * y)
+
+x ? 0  =  x
+x ? y  =  x + dec x
+
+x ? 0  =  x
+x ? y  =  x + dec y
+
+x ? 0  =  x
+x ? y  =  y + dec x
+
+x ? 0  =  x
+x ? y  =  y + dec y
+
+x ? 0  =  x
+x ? y  =  x * dec x
+
+x ? 0  =  x
+x ? y  =  x * dec y
+
+x ? 0  =  x
+x ? y  =  y * dec x
+
+x ? 0  =  x
+x ? y  =  y * dec y
+
+x ? 0  =  0
+x ? y  =  dec (dec (dec x))
+
+x ? 0  =  0
+x ? y  =  dec (dec (dec y))
+
+x ? 0  =  0
+x ? y  =  dec (x * x)
+
+x ? 0  =  0
+x ? y  =  dec (x * y)
+
+x ? 0  =  0
+x ? y  =  dec (y * y)
+
+x ? 0  =  0
+x ? y  =  x + dec x
+
+x ? 0  =  0
+x ? y  =  x + dec y
+
+x ? 0  =  0
+x ? y  =  y + dec x
+
+x ? 0  =  0
+x ? y  =  y + dec y
+
+x ? 0  =  0
+x ? y  =  x * dec x
+
+x ? 0  =  0
+x ? y  =  x * dec y
+
+x ? 0  =  dec x
+x ? y  =  dec (dec x)
+
+x ? 0  =  dec x
+x ? y  =  dec (dec y)
+
+x ? 0  =  dec x
+x ? y  =  x + x
+
+x ? 0  =  dec x
+x ? y  =  x + y
+
+x ? 0  =  dec x
+x ? y  =  y + y
+
+x ? 0  =  dec x
+x ? y  =  x * x
+
+x ? 0  =  dec x
+x ? y  =  x * y
+
+x ? 0  =  dec x
+x ? y  =  y * y
+
+x ? 0  =  dec (dec x)
+x ? y  =  dec x
+
+x ? 0  =  dec (dec x)
+x ? y  =  dec y
+
+x ? 0  =  x + x
+x ? y  =  dec x
+
+x ? 0  =  x + x
+x ? y  =  dec y
+
+x ? 0  =  x * x
+x ? y  =  dec x
+
+x ? 0  =  x * x
+x ? y  =  dec y
+
+x ? 0  =  dec (dec (dec x))
+x ? y  =  x
+
+x ? 0  =  dec (dec (dec x))
+x ? y  =  y
+
+x ? 0  =  dec (dec (dec x))
+x ? y  =  0
+
+x ? 0  =  dec (x * x)
+x ? y  =  x
+
+x ? 0  =  dec (x * x)
+x ? y  =  y
+
+x ? 0  =  dec (x * x)
+x ? y  =  0
+
+x ? 0  =  x + dec x
+x ? y  =  x
+
+x ? 0  =  x + dec x
+x ? y  =  y
+
+x ? 0  =  x + dec x
+x ? y  =  0
+
+x ? 0  =  x * dec x
+x ? y  =  x
+
+x ? 0  =  x * dec x
+x ? y  =  y
+
+x ? 0  =  x * dec x
+x ? y  =  0
+
+0 ? x  =  x
+x ? y  =  dec (dec (dec x))
+
+0 ? x  =  x
+x ? y  =  dec (dec (dec y))
+
+0 ? x  =  x
+x ? y  =  dec (x * x)
+
+0 ? x  =  x
+x ? y  =  dec (x * y)
+
+0 ? x  =  x
+x ? y  =  dec (y * y)
+
+0 ? x  =  x
+x ? y  =  x + dec x
+
+0 ? x  =  x
+x ? y  =  x + dec y
+
+0 ? x  =  x
+x ? y  =  y + dec x
+
+0 ? x  =  x
+x ? y  =  y + dec y
+
+0 ? x  =  x
+x ? y  =  x * dec x
+
+0 ? x  =  x
+x ? y  =  x * dec y
+
+0 ? x  =  x
+x ? y  =  y * dec x
+
+0 ? x  =  x
+x ? y  =  y * dec y
+
+0 ? x  =  0
+x ? y  =  dec (dec (dec x))
+
+0 ? x  =  0
+x ? y  =  dec (dec (dec y))
+
+0 ? x  =  0
+x ? y  =  dec (x * x)
+
+0 ? x  =  0
+x ? y  =  dec (x * y)
+
+0 ? x  =  0
+x ? y  =  dec (y * y)
+
+0 ? x  =  0
+x ? y  =  x + dec x
+
+0 ? x  =  0
+x ? y  =  x + dec y
+
+0 ? x  =  0
+x ? y  =  y + dec x
+
+0 ? x  =  0
+x ? y  =  y + dec y
+
+0 ? x  =  0
+x ? y  =  y * dec x
+
+0 ? x  =  0
+x ? y  =  y * dec y
+
+0 ? x  =  dec x
+x ? y  =  dec (dec x)
+
+0 ? x  =  dec x
+x ? y  =  dec (dec y)
+
+0 ? x  =  dec x
+x ? y  =  x + x
+
+0 ? x  =  dec x
+x ? y  =  x + y
+
+0 ? x  =  dec x
+x ? y  =  y + y
+
+0 ? x  =  dec x
+x ? y  =  x * x
+
+0 ? x  =  dec x
+x ? y  =  x * y
+
+0 ? x  =  dec x
+x ? y  =  y * y
+
+0 ? x  =  dec (dec x)
+x ? y  =  dec x
+
+0 ? x  =  dec (dec x)
+x ? y  =  dec y
+
+0 ? x  =  x + x
+x ? y  =  dec x
+
+0 ? x  =  x + x
+x ? y  =  dec y
+
+0 ? x  =  x * x
+x ? y  =  dec x
+
+0 ? x  =  x * x
+x ? y  =  dec y
+
+0 ? x  =  dec (dec (dec x))
+x ? y  =  x
+
+0 ? x  =  dec (dec (dec x))
+x ? y  =  y
+
+0 ? x  =  dec (dec (dec x))
+x ? y  =  0
+
+0 ? x  =  dec (x * x)
+x ? y  =  x
+
+0 ? x  =  dec (x * x)
+x ? y  =  y
+
+0 ? x  =  dec (x * x)
+x ? y  =  0
+
+0 ? x  =  x + dec x
+x ? y  =  x
+
+0 ? x  =  x + dec x
+x ? y  =  y
+
+0 ? x  =  x + dec x
+x ? y  =  0
+
+0 ? x  =  x * dec x
+x ? y  =  x
+
+0 ? x  =  x * dec x
+x ? y  =  y
+
+0 ? x  =  x * dec x
+x ? y  =  0
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  dec (dec x)
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  dec (dec y)
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  x + x
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  y + y
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  x * x
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  x * y
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  y * y
+
+0 ? x  =  x
+x ? 0  =  0
+x ? y  =  dec (dec x)
+
+0 ? x  =  x
+x ? 0  =  0
+x ? y  =  dec (dec y)
+
+0 ? x  =  x
+x ? 0  =  0
+x ? y  =  x + x
+
+0 ? x  =  x
+x ? 0  =  0
+x ? y  =  x * x
+
+0 ? x  =  x
+x ? 0  =  dec x
+x ? y  =  dec y
+
+0 ? x  =  x
+x ? 0  =  dec (dec x)
+x ? y  =  x
+
+0 ? x  =  x
+x ? 0  =  dec (dec x)
+x ? y  =  0
+
+0 ? x  =  x
+x ? 0  =  x + x
+x ? y  =  x
+
+0 ? x  =  x
+x ? 0  =  x + x
+x ? y  =  0
+
+0 ? x  =  x
+x ? 0  =  x * x
+x ? y  =  x
+
+0 ? x  =  x
+x ? 0  =  x * x
+x ? y  =  0
+
+0 ? x  =  0
+x ? 0  =  x
+x ? y  =  dec (dec x)
+
+0 ? x  =  0
+x ? 0  =  x
+x ? y  =  dec (dec y)
+
+0 ? x  =  0
+x ? 0  =  x
+x ? y  =  y + y
+
+0 ? x  =  0
+x ? 0  =  x
+x ? y  =  y * y
+
+0 ? x  =  0
+x ? 0  =  0
+x ? y  =  dec (dec x)
+
+0 ? x  =  0
+x ? 0  =  0
+x ? y  =  dec (dec y)
+
+0 ? x  =  0
+x ? 0  =  0
+x ? y  =  x + y
+
+0 ? x  =  0
+x ? 0  =  dec x
+x ? y  =  dec y
+
+0 ? x  =  0
+x ? 0  =  dec (dec x)
+x ? y  =  y
+
+0 ? x  =  0
+x ? 0  =  x + x
+x ? y  =  y
+
+0 ? x  =  0
+x ? 0  =  x * x
+x ? y  =  y
+
+0 ? x  =  dec x
+x ? 0  =  x
+x ? y  =  dec x
+
+0 ? x  =  dec x
+x ? 0  =  0
+x ? y  =  dec x
+
+0 ? x  =  dec x
+x ? 0  =  dec x
+x ? y  =  x
+
+0 ? x  =  dec x
+x ? 0  =  dec x
+x ? y  =  y
+
+0 ? x  =  dec x
+x ? 0  =  dec x
+x ? y  =  0
+
+0 ? x  =  dec (dec x)
+x ? 0  =  x
+x ? y  =  y
+
+0 ? x  =  dec (dec x)
+x ? 0  =  x
+x ? y  =  0
+
+0 ? x  =  dec (dec x)
+x ? 0  =  0
+x ? y  =  x
+
+0 ? x  =  x + x
+x ? 0  =  x
+x ? y  =  y
+
+0 ? x  =  x + x
+x ? 0  =  x
+x ? y  =  0
+
+0 ? x  =  x + x
+x ? 0  =  0
+x ? y  =  x
+
+0 ? x  =  x * x
+x ? 0  =  x
+x ? y  =  y
+
+0 ? x  =  x * x
+x ? 0  =  x
+x ? y  =  0
+
+0 ? x  =  x * x
+x ? 0  =  0
+x ? y  =  x
+
+0 ? 0  =  0
+0 ? x  =  dec x
+x ? y  =  dec x
+
+x ? 0  =  x
+x ? y  =  x ? dec y
+
+x ? 0  =  x
+x ? y  =  y ? dec x
+
+x ? 0  =  x
+x ? y  =  y ? dec y
+
+x ? 0  =  x
+x ? y  =  0 ? dec y
+
+x ? 0  =  x
+x ? y  =  dec x ? x
+
+x ? 0  =  x
+x ? y  =  dec x ? y
+
+x ? 0  =  x
+x ? y  =  dec y ? x
+
+0 ? x  =  x
+x ? y  =  x ? dec y
+
+0 ? x  =  x
+x ? y  =  y ? dec x
+
+0 ? x  =  x
+x ? y  =  y ? dec y
+
+0 ? x  =  x
+x ? y  =  dec x ? x
+
+0 ? x  =  x
+x ? y  =  dec x ? y
+
+0 ? x  =  x
+x ? y  =  dec x ? 0
+
+0 ? x  =  x
+x ? y  =  dec y ? x
+
+
+
+allowed patterns:
+
+x ? y  =  _
+
+
+x ? 0  =  _
+x ? y  =  _
+
+0 ? x  =  _
+x ? y  =  _
+
+
+0 ? x  =  _
+x ? 0  =  _
+x ? y  =  _
+
+0 ? 0  =  _
+0 ? x  =  _
+x ? y  =  _
+
+
+0 ? 0  =  _
+0 ? x  =  _
+x ? 0  =  _
+x ? y  =  _
+
+
+
+
+allowed deconstructions:
+
+dec _ :: Int
+dec (dec _) :: Int
+dec (dec (dec _)) :: Int
+
+Candidates for: goo :: [Int] -> [Int]
+  pruning with 4/4 rules
+  [2,0,1,0,1,0,1,0,1] direct candidates, 0 duplicates
+  [2,1,1,3,4,7,10,17,26] pattern candidates, 0 duplicates
+
+rules:
+xs ++ [] == xs
+[] ++ xs == xs
+(xs ++ ys) ++ zs == xs ++ (ys ++ zs)
+(x:xs) ++ ys == x:(xs ++ ys)
+
+direct candidates:
+
+goo xs  =  xs
+
+goo xs  =  []
+
+goo xs  =  xs ++ xs
+
+goo xs  =  xs ++ (xs ++ xs)
+
+
+pattern candidates:
+
+goo xs  =  xs
+
+goo xs  =  []
+
+goo []  =  []
+goo (x:xs)  =  xs
+
+goo xs  =  xs ++ xs
+
+goo []  =  []
+goo (x:xs)  =  x:xs
+
+goo []  =  []
+goo (x:xs)  =  [x]
+
+goo []  =  []
+goo (x:xs)  =  xs ++ xs
+
+goo xs  =  xs ++ (xs ++ xs)
+
+goo []  =  []
+goo (x:xs)  =  x:goo xs
+
+goo []  =  []
+goo (x:xs)  =  xs ++ goo xs
+
+goo []  =  []
+goo (x:xs)  =  goo xs ++ xs
+
+goo []  =  []
+goo (x:xs)  =  x:x:xs
+
+goo []  =  []
+goo (x:xs)  =  [x,x]
+
+goo []  =  []
+goo (x:xs)  =  x:(xs ++ xs)
+
+goo []  =  []
+goo (x:xs)  =  xs ++ (x:xs)
+
+goo []  =  []
+goo (x:xs)  =  xs ++ [x]
+
+goo []  =  []
+goo (x:xs)  =  xs ++ (xs ++ xs)
+
+goo []  =  []
+goo (x:xs)  =  goo xs ++ goo xs
+
+
+
+allowed patterns:
+
+goo xs  =  _
+
+
+goo []  =  _
+goo (x:xs)  =  _
+
+
+
+
+allowed deconstructions:
+
+
+Candidates for: ?? :: [Int] -> [Int] -> [Int]
+  pruning with 4/4 rules
+  [3,0,4,0,8,0,16,0,32] direct candidates, 0 duplicates
+  [3,8,15,45,127,268,845,1565,5692] pattern candidates, 0 duplicates
+
+rules:
+xs ++ [] == xs
+[] ++ xs == xs
+(xs ++ ys) ++ zs == xs ++ (ys ++ zs)
+(x:xs) ++ ys == x:(xs ++ ys)
+
+direct candidates:
+
+xs ?? ys  =  xs
+
+xs ?? ys  =  ys
+
+xs ?? ys  =  []
+
+xs ?? ys  =  xs ++ xs
+
+xs ?? ys  =  xs ++ ys
+
+xs ?? ys  =  ys ++ xs
+
+xs ?? ys  =  ys ++ ys
+
+xs ?? ys  =  xs ++ (xs ++ xs)
+
+xs ?? ys  =  xs ++ (xs ++ ys)
+
+xs ?? ys  =  xs ++ (ys ++ xs)
+
+xs ?? ys  =  xs ++ (ys ++ ys)
+
+xs ?? ys  =  ys ++ (xs ++ xs)
+
+xs ?? ys  =  ys ++ (xs ++ ys)
+
+xs ?? ys  =  ys ++ (ys ++ xs)
+
+xs ?? ys  =  ys ++ (ys ++ ys)
+
+
+pattern candidates:
+
+xs ?? ys  =  xs
+
+xs ?? ys  =  ys
+
+xs ?? ys  =  []
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  []
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  []
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys
+
+xs ?? ys  =  xs ++ xs
+
+xs ?? ys  =  xs ++ ys
+
+xs ?? ys  =  ys ++ xs
+
+xs ?? ys  =  ys ++ ys
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  []
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  []
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? xs  =  []
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? xs  =  []
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? xs  =  []
+(x:xs) ?? []  =  []
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? xs  =  []
+(x:xs) ?? []  =  []
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? ys  =  xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? ys  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? ys  =  []
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  x:xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  x:ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  [x]
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ++ xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ++ ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ++ xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ++ ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  x:xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  x:ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  [x]
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ++ xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ++ ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ++ xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ++ ys
+
+xs ?? []  =  xs ++ xs
+xs ?? (x:ys)  =  xs
+
+xs ?? []  =  xs ++ xs
+xs ?? (x:ys)  =  ys
+
+xs ?? []  =  xs ++ xs
+xs ?? (x:ys)  =  []
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  x:xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  x:ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  [x]
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ++ xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ++ ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:ys
+
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+(x:xs) ?? ys  =  xs ++ (ys ++ ys)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ (x:xs)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ (x:ys)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ [x]
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ (xs ++ xs)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ (xs ++ ys)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ (ys ++ xs)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ (ys ++ ys)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:x:xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:x:ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  [x,x]
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:(xs ++ xs)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:(xs ++ ys)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:(ys ++ xs)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:(ys ++ ys)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ (x:xs)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ (x:ys)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ [x]
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ (xs ++ xs)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ (xs ++ ys)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ (ys ++ xs)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ (ys ++ ys)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ (x:xs)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ (x:ys)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ [x]
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ (xs ++ xs)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ (xs ++ ys)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ (ys ++ xs)
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ (ys ++ ys)
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  x:xs
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  x:ys
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  [x]
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  xs ++ xs
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  xs ++ ys
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  ys ++ xs
+
+[] ?? xs  =  xs ++ (xs ++ xs)
+(x:xs) ?? ys  =  xs
+
+[] ?? xs  =  xs ++ (xs ++ xs)
+(x:xs) ?? ys  =  ys
+
+[] ?? xs  =  xs ++ (xs ++ xs)
+(x:xs) ?? ys  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  x:xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  x:ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  [x]
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  y:xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  y:ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  [y]
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  xs ++ xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  xs ++ ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys ++ xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys ++ ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  x:xs
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  x:xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  [x]
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  [x]
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs ++ xs
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs ++ xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  x:xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  x:xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  [x]
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  [x]
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs ++ xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs ++ xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  []
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  x:xs ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  x:ys ?? xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  x:ys ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  x:[] ?? xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  x:[] ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ++ xs ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ++ ys ?? xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ++ ys ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ++ [] ?? xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ++ [] ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ++ xs ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ++ ys ?? xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ++ ys ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ++ [] ?? xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ++ [] ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ?? ys ++ xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ?? xs ++ xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ?? ys ++ xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  [] ?? xs ++ xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  [] ?? ys ++ xs
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  xs ?? ys ++ ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ?? xs ++ ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ?? ys ++ ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  [] ?? xs ++ ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  [] ?? ys ++ ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  x:xs ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  x:ys ?? xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  x:ys ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  x:[] ?? xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  x:[] ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ++ xs ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ++ ys ?? xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ++ ys ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ++ [] ?? xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ++ [] ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ++ xs ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ++ ys ?? xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ++ ys ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ++ [] ?? xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ++ [] ?? ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ?? ys ++ xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ?? xs ++ xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ?? ys ++ xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  [] ?? xs ++ xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  [] ?? ys ++ xs
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  xs ?? ys ++ ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ?? xs ++ ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  ys ?? ys ++ ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  [] ?? xs ++ ys
+
+xs ?? []  =  []
+xs ?? (x:ys)  =  [] ?? ys ++ ys
+
+xs ?? []  =  xs ++ xs
+xs ?? (x:ys)  =  xs ?? ys
+
+xs ?? []  =  xs ++ xs
+xs ?? (x:ys)  =  ys ?? xs
+
+xs ?? []  =  xs ++ xs
+xs ?? (x:ys)  =  ys ?? ys
+
+xs ?? []  =  xs ++ xs
+xs ?? (x:ys)  =  [] ?? xs
+
+xs ?? []  =  xs ++ xs
+xs ?? (x:ys)  =  [] ?? ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  x:xs ?? xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  x:xs ?? ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  x:xs ?? []
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  x:ys ?? xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  x:ys ?? []
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ++ xs ?? xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ++ xs ?? ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ++ xs ?? []
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ++ ys ?? xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ++ ys ?? []
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ xs ?? xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ xs ?? ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ xs ?? []
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ ys ?? xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ++ ys ?? []
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? xs ++ xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? ys ++ xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? [] ++ xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ?? xs ++ xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ?? [] ++ xs
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? xs ++ ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? ys ++ ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? [] ++ ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ?? xs ++ ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  ys ?? [] ++ ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:xs ?? xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:xs ?? ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:xs ?? []
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:ys ?? xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  x:ys ?? []
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ xs ?? xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ xs ?? ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ xs ?? []
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ ys ?? xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ++ ys ?? []
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ xs ?? xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ xs ?? ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ xs ?? []
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ ys ?? xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ++ ys ?? []
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ?? xs ++ xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ?? ys ++ xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ?? [] ++ xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ?? xs ++ xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ?? [] ++ xs
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ?? xs ++ ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ?? ys ++ ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  xs ?? [] ++ ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ?? xs ++ ys
+
+[] ?? xs  =  []
+(x:xs) ?? ys  =  ys ?? [] ++ ys
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  xs ?? xs
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  xs ?? ys
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  xs ?? []
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  ys ?? xs
+
+[] ?? xs  =  xs ++ xs
+(x:xs) ?? ys  =  ys ?? []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  xs ?? xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  xs ?? ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  xs ?? []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys ?? xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys ?? ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys ?? []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  [] ?? xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  [] ?? ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs ?? xs
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs ?? []
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  [] ?? xs
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs ?? xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  xs ?? []
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? []  =  [] ?? xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs ?? xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs ?? []
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  [] ?? xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs ?? xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs ?? []
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  []
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  [] ?? xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  []
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  (x:xs) ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  (x:ys) ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  [x] ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  (xs ++ xs) ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  (xs ++ ys) ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  (ys ++ xs) ?? ys
+
+xs ?? []  =  xs
+xs ?? (x:ys)  =  (ys ++ ys) ?? ys
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? (x:xs)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? (x:ys)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? [x]
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? (xs ++ xs)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? (xs ++ ys)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? (ys ++ xs)
+
+[] ?? xs  =  xs
+(x:xs) ?? ys  =  xs ?? (ys ++ ys)
+
+
+
+allowed patterns:
+
+xs ?? ys  =  _
+
+
+xs ?? []  =  _
+xs ?? (x:ys)  =  _
+
+[] ?? xs  =  _
+(x:xs) ?? ys  =  _
+
+
+[] ?? xs  =  _
+(x:xs) ?? []  =  _
+(x:xs) ?? (y:ys)  =  _
+
+[] ?? []  =  _
+[] ?? (x:xs)  =  _
+(x:xs) ?? ys  =  _
+
+
+[] ?? []  =  _
+[] ?? (x:xs)  =  _
+(x:xs) ?? []  =  _
+(x:xs) ?? (y:ys)  =  _
+
+
+
+
+allowed deconstructions:
+
+
+Candidates for: ton :: Bool -> Bool
+  pruning with 39/49 rules
+  [3,1,0,0,0,0,0,0,0] direct candidates, 0 duplicates
+  [3,3,0,0,0,0,0,0,0] pattern candidates, 0 duplicates
+
+rules:
+not False == True
+not True == False
+p && p == p
+p || p == p
+not (not p) == p
+p && False == False
+p && True == p
+False && p == False
+True && p == p
+p || False == p
+p || True == True
+False || p == p
+True || p == True
+not (p && q) == not p || not q
+not (p && q) == not q || not p
+not (p || q) == not p && not q
+not (p || q) == not q && not p
+p && not p == False
+not p && p == False
+p || not p == True
+not p || p == True
+(p && q) && r == p && (q && r)
+(p && q) && r == q && (p && r)
+(p || q) || r == p || (q || r)
+(p || q) || r == q || (p || r)
+p && (p && q) == p && q
+p && (q && p) == p && q
+p && (q && p) == q && p
+p || (p || q) == p || q
+p || (q || p) == p || q
+p || (q || p) == q || p
+p && (p || q) == p
+p && (q || p) == p
+(p || q) && p == p
+(p || q) && q == q
+p || p && q == p
+p || q && p == p
+p && q || p == p
+p && q || q == q
+equations:
+q && p == p && q
+q || p == p || q
+q && (p && r) == p && (q && r)
+r && (p && q) == p && (q && r)
+r && (q && p) == p && (q && r)
+q || (p || r) == p || (q || r)
+r || (p || q) == p || (q || r)
+r || (q || p) == p || (q || r)
+(r || q) && p == p && (q || r)
+r && q || p == p || q && r
+
+direct candidates:
+
+ton p  =  p
+
+ton p  =  False
+
+ton p  =  True
+
+ton p  =  not p
+
+
+pattern candidates:
+
+ton p  =  p
+
+ton p  =  False
+
+ton p  =  True
+
+ton p  =  not p
+
+ton False  =  False
+ton True  =  True
+
+ton False  =  True
+ton True  =  False
+
+
+
+allowed patterns:
+
+ton p  =  _
+
+
+ton False  =  _
+ton True  =  _
+
+
+
+
+allowed deconstructions:
+
+
+Candidates for: &| :: Bool -> Bool -> Bool
+  pruning with 39/49 rules
+  [4,2,2,4,2,16,17,56,110] direct candidates, 0 duplicates
+  [4,14,26,10,2,16,17,56,110] pattern candidates, 0 duplicates
+
+rules:
+not False == True
+not True == False
+p && p == p
+p || p == p
+not (not p) == p
+p && False == False
+p && True == p
+False && p == False
+True && p == p
+p || False == p
+p || True == True
+False || p == p
+True || p == True
+not (p && q) == not p || not q
+not (p && q) == not q || not p
+not (p || q) == not p && not q
+not (p || q) == not q && not p
+p && not p == False
+not p && p == False
+p || not p == True
+not p || p == True
+(p && q) && r == p && (q && r)
+(p && q) && r == q && (p && r)
+(p || q) || r == p || (q || r)
+(p || q) || r == q || (p || r)
+p && (p && q) == p && q
+p && (q && p) == p && q
+p && (q && p) == q && p
+p || (p || q) == p || q
+p || (q || p) == p || q
+p || (q || p) == q || p
+p && (p || q) == p
+p && (q || p) == p
+(p || q) && p == p
+(p || q) && q == q
+p || p && q == p
+p || q && p == p
+p && q || p == p
+p && q || q == q
+equations:
+q && p == p && q
+q || p == p || q
+q && (p && r) == p && (q && r)
+r && (p && q) == p && (q && r)
+r && (q && p) == p && (q && r)
+q || (p || r) == p || (q || r)
+r || (p || q) == p || (q || r)
+r || (q || p) == p || (q || r)
+(r || q) && p == p && (q || r)
+r && q || p == p || q && r
+
+direct candidates:
+
+p &| q  =  p
+
+p &| q  =  q
+
+p &| q  =  False
+
+p &| q  =  True
+
+p &| q  =  not p
+
+p &| q  =  not q
+
+p &| q  =  p && q
+
+p &| q  =  p || q
+
+p &| q  =  p && not q
+
+p &| q  =  q && not p
+
+p &| q  =  p || not q
+
+p &| q  =  q || not p
+
+p &| q  =  not p && not q
+
+p &| q  =  not p || not q
+
+p &| q  =  p && (q && not p)
+
+p &| q  =  p && (q || not p)
+
+p &| q  =  q && (p && not q)
+
+p &| q  =  q && (p || not q)
+
+p &| q  =  p || q && not p
+
+p &| q  =  p || (q || not p)
+
+p &| q  =  q || p && not q
+
+p &| q  =  q || (p || not q)
+
+p &| q  =  not p && (p && q)
+
+p &| q  =  not p && (p || q)
+
+p &| q  =  not q && (p && q)
+
+p &| q  =  not q && (p || q)
+
+p &| q  =  not p || p && q
+
+p &| q  =  not p || (p || q)
+
+p &| q  =  not q || p && q
+
+p &| q  =  not q || (p || q)
+
+
+pattern candidates:
+
+p &| q  =  p
+
+p &| q  =  q
+
+p &| q  =  False
+
+p &| q  =  True
+
+p &| q  =  not p
+
+p &| q  =  not q
+
+p &| False  =  p
+p &| True  =  False
+
+p &| False  =  p
+p &| True  =  True
+
+p &| False  =  False
+p &| True  =  p
+
+p &| False  =  False
+p &| True  =  True
+
+p &| False  =  True
+p &| True  =  p
+
+p &| False  =  True
+p &| True  =  False
+
+False &| p  =  p
+True &| p  =  False
+
+False &| p  =  p
+True &| p  =  True
+
+False &| p  =  False
+True &| p  =  p
+
+False &| p  =  False
+True &| p  =  True
+
+False &| p  =  True
+True &| p  =  p
+
+False &| p  =  True
+True &| p  =  False
+
+p &| q  =  p && q
+
+p &| q  =  p || q
+
+p &| False  =  p
+p &| True  =  not p
+
+p &| False  =  False
+p &| True  =  not p
+
+p &| False  =  True
+p &| True  =  not p
+
+p &| False  =  not p
+p &| True  =  p
+
+p &| False  =  not p
+p &| True  =  False
+
+p &| False  =  not p
+p &| True  =  True
+
+False &| p  =  p
+True &| p  =  not p
+
+False &| p  =  False
+True &| p  =  not p
+
+False &| p  =  True
+True &| p  =  not p
+
+False &| p  =  not p
+True &| p  =  p
+
+False &| p  =  not p
+True &| p  =  False
+
+False &| p  =  not p
+True &| p  =  True
+
+False &| p  =  p
+True &| False  =  False
+True &| True  =  True
+
+False &| p  =  p
+True &| False  =  True
+True &| True  =  False
+
+False &| p  =  False
+True &| False  =  False
+True &| True  =  True
+
+False &| p  =  False
+True &| False  =  True
+True &| True  =  False
+
+False &| p  =  True
+True &| False  =  False
+True &| True  =  True
+
+False &| p  =  True
+True &| False  =  True
+True &| True  =  False
+
+False &| False  =  False
+False &| True  =  True
+True &| p  =  p
+
+False &| False  =  False
+False &| True  =  True
+True &| p  =  False
+
+False &| False  =  False
+False &| True  =  True
+True &| p  =  True
+
+False &| False  =  True
+False &| True  =  False
+True &| p  =  p
+
+False &| False  =  True
+False &| True  =  False
+True &| p  =  False
+
+False &| False  =  True
+False &| True  =  False
+True &| p  =  True
+
+p &| q  =  p && not q
+
+p &| q  =  q && not p
+
+p &| q  =  p || not q
+
+p &| q  =  q || not p
+
+False &| p  =  not p
+True &| False  =  False
+True &| True  =  True
+
+False &| p  =  not p
+True &| False  =  True
+True &| True  =  False
+
+False &| False  =  False
+False &| True  =  True
+True &| p  =  not p
+
+False &| False  =  True
+False &| True  =  False
+True &| p  =  not p
+
+False &| False  =  False
+False &| True  =  True
+True &| False  =  True
+True &| True  =  False
+
+False &| False  =  True
+False &| True  =  False
+True &| False  =  False
+True &| True  =  True
+
+p &| q  =  not p && not q
+
+p &| q  =  not p || not q
+
+p &| q  =  p && (q && not p)
+
+p &| q  =  p && (q || not p)
+
+p &| q  =  q && (p && not q)
+
+p &| q  =  q && (p || not q)
+
+p &| q  =  p || q && not p
+
+p &| q  =  p || (q || not p)
+
+p &| q  =  q || p && not q
+
+p &| q  =  q || (p || not q)
+
+p &| q  =  not p && (p && q)
+
+p &| q  =  not p && (p || q)
+
+p &| q  =  not q && (p && q)
+
+p &| q  =  not q && (p || q)
+
+p &| q  =  not p || p && q
+
+p &| q  =  not p || (p || q)
+
+p &| q  =  not q || p && q
+
+p &| q  =  not q || (p || q)
+
+
+
+allowed patterns:
+
+p &| q  =  _
+
+
+p &| False  =  _
+p &| True  =  _
+
+False &| p  =  _
+True &| p  =  _
+
+
+False &| p  =  _
+True &| False  =  _
+True &| True  =  _
+
+False &| False  =  _
+False &| True  =  _
+True &| p  =  _
+
+
+False &| False  =  _
+False &| True  =  _
+True &| False  =  _
+True &| True  =  _
+
+
+
+
+allowed deconstructions:
+
+
+Candidates for: gcd :: Int -> Int -> Int
+  pruning with 0/0 rules
+  [3,0,9,0,54,0,405,0,3402] direct candidates, 0 duplicates
+  [3,6,11,50,98,330,774,2714,6660] pattern candidates, 0 duplicates
+
+no rules.
+
+direct candidates:
+
+gcd x y  =  x
+
+gcd x y  =  y
+
+gcd x y  =  0
+
+gcd x y  =  x `mod` x
+
+gcd x y  =  x `mod` y
+
+gcd x y  =  x `mod` 0
+
+gcd x y  =  y `mod` x
+
+gcd x y  =  y `mod` y
+
+gcd x y  =  y `mod` 0
+
+gcd x y  =  0 `mod` x
+
+gcd x y  =  0 `mod` y
+
+gcd x y  =  0 `mod` 0
+
+gcd x y  =  x `mod` (x `mod` x)
+
+gcd x y  =  x `mod` (x `mod` y)
+
+gcd x y  =  x `mod` (x `mod` 0)
+
+gcd x y  =  x `mod` (y `mod` x)
+
+gcd x y  =  x `mod` (y `mod` y)
+
+gcd x y  =  x `mod` (y `mod` 0)
+
+gcd x y  =  x `mod` (0 `mod` x)
+
+gcd x y  =  x `mod` (0 `mod` y)
+
+gcd x y  =  x `mod` (0 `mod` 0)
+
+gcd x y  =  y `mod` (x `mod` x)
+
+gcd x y  =  y `mod` (x `mod` y)
+
+gcd x y  =  y `mod` (x `mod` 0)
+
+gcd x y  =  y `mod` (y `mod` x)
+
+gcd x y  =  y `mod` (y `mod` y)
+
+gcd x y  =  y `mod` (y `mod` 0)
+
+gcd x y  =  y `mod` (0 `mod` x)
+
+gcd x y  =  y `mod` (0 `mod` y)
+
+gcd x y  =  y `mod` (0 `mod` 0)
+
+gcd x y  =  0 `mod` (x `mod` x)
+
+gcd x y  =  0 `mod` (x `mod` y)
+
+gcd x y  =  0 `mod` (x `mod` 0)
+
+gcd x y  =  0 `mod` (y `mod` x)
+
+gcd x y  =  0 `mod` (y `mod` y)
+
+gcd x y  =  0 `mod` (y `mod` 0)
+
+gcd x y  =  0 `mod` (0 `mod` x)
+
+gcd x y  =  0 `mod` (0 `mod` y)
+
+gcd x y  =  0 `mod` (0 `mod` 0)
+
+gcd x y  =  (x `mod` x) `mod` x
+
+gcd x y  =  (x `mod` x) `mod` y
+
+gcd x y  =  (x `mod` x) `mod` 0
+
+gcd x y  =  (x `mod` y) `mod` x
+
+gcd x y  =  (x `mod` y) `mod` y
+
+gcd x y  =  (x `mod` y) `mod` 0
+
+gcd x y  =  (x `mod` 0) `mod` x
+
+gcd x y  =  (x `mod` 0) `mod` y
+
+gcd x y  =  (x `mod` 0) `mod` 0
+
+gcd x y  =  (y `mod` x) `mod` x
+
+gcd x y  =  (y `mod` x) `mod` y
+
+gcd x y  =  (y `mod` x) `mod` 0
+
+gcd x y  =  (y `mod` y) `mod` x
+
+gcd x y  =  (y `mod` y) `mod` y
+
+gcd x y  =  (y `mod` y) `mod` 0
+
+gcd x y  =  (y `mod` 0) `mod` x
+
+gcd x y  =  (y `mod` 0) `mod` y
+
+gcd x y  =  (y `mod` 0) `mod` 0
+
+gcd x y  =  (0 `mod` x) `mod` x
+
+gcd x y  =  (0 `mod` x) `mod` y
+
+gcd x y  =  (0 `mod` x) `mod` 0
+
+gcd x y  =  (0 `mod` y) `mod` x
+
+gcd x y  =  (0 `mod` y) `mod` y
+
+gcd x y  =  (0 `mod` y) `mod` 0
+
+gcd x y  =  (0 `mod` 0) `mod` x
+
+gcd x y  =  (0 `mod` 0) `mod` y
+
+gcd x y  =  (0 `mod` 0) `mod` 0
+
+
+pattern candidates:
+
+gcd x y  =  x
+
+gcd x y  =  y
+
+gcd x y  =  0
+
+gcd x 0  =  x
+gcd x y  =  y
+
+gcd x 0  =  x
+gcd x y  =  0
+
+gcd x 0  =  0
+gcd x y  =  x
+
+gcd 0 x  =  x
+gcd x y  =  x
+
+gcd 0 x  =  x
+gcd x y  =  0
+
+gcd 0 x  =  0
+gcd x y  =  y
+
+gcd x y  =  x `mod` x
+
+gcd x y  =  x `mod` y
+
+gcd x y  =  x `mod` 0
+
+gcd x y  =  y `mod` x
+
+gcd x y  =  y `mod` y
+
+gcd x y  =  y `mod` 0
+
+gcd x y  =  0 `mod` x
+
+gcd x y  =  0 `mod` y
+
+gcd 0 x  =  x
+gcd x 0  =  x
+gcd x y  =  0
+
+gcd 0 x  =  x
+gcd x 0  =  0
+gcd x y  =  x
+
+gcd 0 x  =  0
+gcd x 0  =  x
+gcd x y  =  y
+
+gcd x 0  =  x
+gcd x y  =  x `mod` x
+
+gcd x 0  =  x
+gcd x y  =  x `mod` y
+
+gcd x 0  =  x
+gcd x y  =  x `mod` 0
+
+gcd x 0  =  x
+gcd x y  =  y `mod` x
+
+gcd x 0  =  x
+gcd x y  =  y `mod` y
+
+gcd x 0  =  x
+gcd x y  =  y `mod` 0
+
+gcd x 0  =  x
+gcd x y  =  0 `mod` x
+
+gcd x 0  =  x
+gcd x y  =  0 `mod` y
+
+gcd x 0  =  0
+gcd x y  =  x `mod` x
+
+gcd x 0  =  0
+gcd x y  =  x `mod` y
+
+gcd x 0  =  0
+gcd x y  =  x `mod` 0
+
+gcd x 0  =  0
+gcd x y  =  y `mod` x
+
+gcd x 0  =  0
+gcd x y  =  y `mod` y
+
+gcd x 0  =  0
+gcd x y  =  y `mod` 0
+
+gcd x 0  =  0
+gcd x y  =  0 `mod` x
+
+gcd x 0  =  0
+gcd x y  =  0 `mod` y
+
+gcd x 0  =  x `mod` x
+gcd x y  =  x
+
+gcd x 0  =  x `mod` x
+gcd x y  =  y
+
+gcd x 0  =  x `mod` x
+gcd x y  =  0
+
+gcd x 0  =  x `mod` 0
+gcd x y  =  x
+
+gcd x 0  =  x `mod` 0
+gcd x y  =  y
+
+gcd x 0  =  x `mod` 0
+gcd x y  =  0
+
+gcd x 0  =  0 `mod` x
+gcd x y  =  x
+
+gcd x 0  =  0 `mod` x
+gcd x y  =  y
+
+gcd x 0  =  0 `mod` x
+gcd x y  =  0
+
+gcd 0 x  =  x
+gcd x y  =  x `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  x `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  x `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  y `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  y `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  y `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` y
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  x
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  y
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  0
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  x
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  y
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  0
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  x
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  y
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  0
+
+gcd x y  =  x `mod` (x `mod` x)
+
+gcd x y  =  x `mod` (x `mod` y)
+
+gcd x y  =  x `mod` (x `mod` 0)
+
+gcd x y  =  x `mod` (y `mod` x)
+
+gcd x y  =  x `mod` (y `mod` y)
+
+gcd x y  =  x `mod` (y `mod` 0)
+
+gcd x y  =  x `mod` (0 `mod` x)
+
+gcd x y  =  x `mod` (0 `mod` y)
+
+gcd x y  =  y `mod` (x `mod` x)
+
+gcd x y  =  y `mod` (x `mod` y)
+
+gcd x y  =  y `mod` (x `mod` 0)
+
+gcd x y  =  y `mod` (y `mod` x)
+
+gcd x y  =  y `mod` (y `mod` y)
+
+gcd x y  =  y `mod` (y `mod` 0)
+
+gcd x y  =  y `mod` (0 `mod` x)
+
+gcd x y  =  y `mod` (0 `mod` y)
+
+gcd x y  =  0 `mod` (x `mod` x)
+
+gcd x y  =  0 `mod` (x `mod` y)
+
+gcd x y  =  0 `mod` (x `mod` 0)
+
+gcd x y  =  0 `mod` (y `mod` x)
+
+gcd x y  =  0 `mod` (y `mod` y)
+
+gcd x y  =  0 `mod` (y `mod` 0)
+
+gcd x y  =  0 `mod` (0 `mod` x)
+
+gcd x y  =  0 `mod` (0 `mod` y)
+
+gcd x y  =  (x `mod` x) `mod` x
+
+gcd x y  =  (x `mod` x) `mod` y
+
+gcd x y  =  (x `mod` x) `mod` 0
+
+gcd x y  =  (x `mod` y) `mod` x
+
+gcd x y  =  (x `mod` y) `mod` y
+
+gcd x y  =  (x `mod` y) `mod` 0
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+gcd x y  =  (x `mod` 0) `mod` x
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+gcd x y  =  (x `mod` 0) `mod` y
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+gcd x y  =  (x `mod` 0) `mod` 0
+
+gcd x y  =  (y `mod` x) `mod` x
+
+gcd x y  =  (y `mod` x) `mod` y
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+gcd x y  =  (y `mod` x) `mod` 0
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+gcd x y  =  (y `mod` y) `mod` x
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+gcd x y  =  (y `mod` y) `mod` y
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+gcd x y  =  (y `mod` y) `mod` 0
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+gcd x y  =  (y `mod` 0) `mod` x
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+gcd x y  =  (y `mod` 0) `mod` y
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+gcd x y  =  (y `mod` 0) `mod` 0
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+gcd x y  =  (0 `mod` x) `mod` x
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+gcd x y  =  (0 `mod` x) `mod` y
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+gcd x y  =  (0 `mod` x) `mod` 0
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+gcd x y  =  (0 `mod` y) `mod` x
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+gcd x y  =  (0 `mod` y) `mod` y
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+gcd x y  =  (0 `mod` y) `mod` 0
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  0
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+gcd 0 x  =  x `mod` x
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+gcd 0 x  =  x `mod` x
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+gcd 0 x  =  x `mod` x
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+gcd 0 x  =  x `mod` 0
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+gcd 0 x  =  x `mod` 0
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+gcd 0 x  =  x `mod` 0
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+gcd 0 x  =  0 `mod` x
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+gcd 0 x  =  0 `mod` x
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+gcd 0 x  =  0 `mod` x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
+gcd x y  =  (x `mod` x) `mod` x
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+gcd x 0  =  x
+gcd x y  =  (x `mod` x) `mod` y
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+gcd x 0  =  x
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+gcd x 0  =  x
+gcd x y  =  (x `mod` y) `mod` x
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+gcd x 0  =  x
+gcd x y  =  (x `mod` y) `mod` y
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  x
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
+gcd x y  =  y `mod` (y `mod` y)
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
+gcd x y  =  (x `mod` x) `mod` x
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+gcd x 0  =  0
+gcd x y  =  (x `mod` x) `mod` y
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+gcd x 0  =  0
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+gcd x 0  =  0
+gcd x y  =  (x `mod` y) `mod` x
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+gcd x 0  =  0
+gcd x y  =  (x `mod` y) `mod` y
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
+gcd x y  =  (y `mod` x) `mod` y
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  0
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+gcd x 0  =  x `mod` x
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+gcd x 0  =  x `mod` x
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+gcd x 0  =  x `mod` x
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+gcd x 0  =  x `mod` x
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+gcd x 0  =  x `mod` x
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+gcd x 0  =  x `mod` x
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+gcd x 0  =  x `mod` x
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+gcd x 0  =  x `mod` 0
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+gcd x 0  =  x `mod` 0
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+gcd x 0  =  x `mod` 0
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+gcd x 0  =  x `mod` 0
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+gcd x 0  =  x `mod` 0
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+gcd x 0  =  x `mod` 0
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+gcd x 0  =  0 `mod` x
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+gcd x 0  =  0 `mod` x
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+gcd x 0  =  0 `mod` x
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+gcd x 0  =  0 `mod` x
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+gcd x 0  =  0 `mod` x
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+gcd x 0  =  0 `mod` x
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+gcd x 0  =  x `mod` (x `mod` x)
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+gcd x 0  =  x `mod` (x `mod` x)
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+gcd x 0  =  x `mod` (x `mod` x)
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+gcd x 0  =  x `mod` (x `mod` 0)
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+gcd x 0  =  x `mod` (x `mod` 0)
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+gcd x 0  =  x `mod` (x `mod` 0)
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+gcd x 0  =  x `mod` (0 `mod` x)
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+gcd x 0  =  x `mod` (0 `mod` x)
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+gcd x 0  =  x `mod` (0 `mod` x)
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+gcd x 0  =  0 `mod` (x `mod` x)
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+gcd x 0  =  0 `mod` (x `mod` x)
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+gcd x 0  =  0 `mod` (x `mod` x)
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+gcd x 0  =  0 `mod` (x `mod` 0)
+gcd x y  =  x
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+gcd x 0  =  0 `mod` (x `mod` 0)
+gcd x y  =  y
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+gcd x 0  =  0 `mod` (x `mod` 0)
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+gcd x 0  =  0 `mod` (0 `mod` x)
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+gcd x 0  =  0 `mod` (0 `mod` x)
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+gcd x 0  =  0 `mod` (0 `mod` x)
+gcd x y  =  0
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+gcd x 0  =  (x `mod` x) `mod` x
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+gcd x 0  =  (x `mod` x) `mod` x
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+gcd x 0  =  (x `mod` x) `mod` x
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+gcd x 0  =  (x `mod` x) `mod` 0
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+gcd x 0  =  (x `mod` x) `mod` 0
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+gcd x 0  =  (x `mod` x) `mod` 0
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+gcd x 0  =  (x `mod` 0) `mod` x
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+gcd x 0  =  (x `mod` 0) `mod` x
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+gcd x 0  =  (x `mod` 0) `mod` x
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+gcd x 0  =  (x `mod` 0) `mod` 0
+gcd x y  =  x
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+gcd x 0  =  (x `mod` 0) `mod` 0
+gcd x y  =  y
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+gcd x 0  =  (x `mod` 0) `mod` 0
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+gcd x 0  =  (0 `mod` x) `mod` x
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+gcd x 0  =  (0 `mod` x) `mod` x
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+gcd x 0  =  (0 `mod` x) `mod` x
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+gcd x 0  =  (0 `mod` x) `mod` 0
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+gcd x 0  =  (0 `mod` x) `mod` 0
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+gcd x 0  =  (0 `mod` x) `mod` 0
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+gcd 0 x  =  x
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+gcd 0 x  =  x
+gcd x y  =  x `mod` (x `mod` y)
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+gcd 0 x  =  x
+gcd x y  =  x `mod` (x `mod` 0)
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+gcd 0 x  =  x
+gcd x y  =  x `mod` (y `mod` x)
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+gcd 0 x  =  x
+gcd x y  =  x `mod` (y `mod` y)
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+gcd 0 x  =  x
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+gcd 0 x  =  x
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+gcd 0 x  =  x
+gcd x y  =  x `mod` (0 `mod` y)
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+gcd 0 x  =  x
+gcd x y  =  y `mod` (x `mod` x)
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+gcd 0 x  =  x
+gcd x y  =  y `mod` (x `mod` y)
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+gcd 0 x  =  x
+gcd x y  =  y `mod` (x `mod` 0)
+
+gcd 0 x  =  x
+gcd x y  =  y `mod` (y `mod` x)
+
+gcd 0 x  =  x
+gcd x y  =  y `mod` (y `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  y `mod` (y `mod` 0)
+
+gcd 0 x  =  x
+gcd x y  =  y `mod` (0 `mod` x)
+
+gcd 0 x  =  x
+gcd x y  =  y `mod` (0 `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` (x `mod` x)
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` (x `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` (x `mod` 0)
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` (y `mod` x)
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` (y `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` (y `mod` 0)
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` (0 `mod` x)
+
+gcd 0 x  =  x
+gcd x y  =  0 `mod` (0 `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` x) `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` x) `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` x) `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` y) `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` y) `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` y) `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` 0) `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` 0) `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  (x `mod` 0) `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` x) `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` x) `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` x) `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` y) `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` y) `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` y) `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` 0) `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` 0) `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  (y `mod` 0) `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  (0 `mod` x) `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  (0 `mod` x) `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  (0 `mod` x) `mod` 0
+
+gcd 0 x  =  x
+gcd x y  =  (0 `mod` y) `mod` x
+
+gcd 0 x  =  x
+gcd x y  =  (0 `mod` y) `mod` y
+
+gcd 0 x  =  x
+gcd x y  =  (0 `mod` y) `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` (x `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` (x `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` (x `mod` 0)
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` (y `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` (y `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` (y `mod` 0)
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` (0 `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  x `mod` (0 `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` (x `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` (x `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` (x `mod` 0)
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` (y `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` (y `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` (y `mod` 0)
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` (0 `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  y `mod` (0 `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` (x `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` (x `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` (x `mod` 0)
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` (y `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` (y `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` (y `mod` 0)
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` (0 `mod` x)
+
+gcd 0 x  =  0
+gcd x y  =  0 `mod` (0 `mod` y)
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` x) `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` x) `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` x) `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` y) `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` y) `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` y) `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` 0) `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` 0) `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  (x `mod` 0) `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` x) `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` x) `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` x) `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` y) `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` y) `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` y) `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` 0) `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` 0) `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  (y `mod` 0) `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  (0 `mod` x) `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  (0 `mod` x) `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  (0 `mod` x) `mod` 0
+
+gcd 0 x  =  0
+gcd x y  =  (0 `mod` y) `mod` x
+
+gcd 0 x  =  0
+gcd x y  =  (0 `mod` y) `mod` y
+
+gcd 0 x  =  0
+gcd x y  =  (0 `mod` y) `mod` 0
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  x `mod` x
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  x `mod` y
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  x `mod` 0
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  y `mod` x
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  y `mod` 0
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  0 `mod` x
+
+gcd 0 x  =  x `mod` x
+gcd x y  =  0 `mod` y
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  x `mod` x
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  x `mod` y
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  x `mod` 0
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  y `mod` y
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  0 `mod` x
+
+gcd 0 x  =  x `mod` 0
+gcd x y  =  0 `mod` y
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  x `mod` x
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  x `mod` 0
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  y `mod` x
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  y `mod` y
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  y `mod` 0
+
+gcd 0 x  =  0 `mod` x
+gcd x y  =  0 `mod` x
+
+gcd 0 x  =  x `mod` (x `mod` x)
+gcd x y  =  x
+
+gcd 0 x  =  x `mod` (x `mod` x)
+gcd x y  =  y
+
+gcd 0 x  =  x `mod` (x `mod` x)
+gcd x y  =  0
+
+gcd 0 x  =  x `mod` (x `mod` 0)
+gcd x y  =  x
+
+gcd 0 x  =  x `mod` (x `mod` 0)
+gcd x y  =  y
+
+gcd 0 x  =  x `mod` (x `mod` 0)
+gcd x y  =  0
+
+gcd 0 x  =  x `mod` (0 `mod` x)
+gcd x y  =  x
+
+gcd 0 x  =  x `mod` (0 `mod` x)
+gcd x y  =  y
+
+gcd 0 x  =  x `mod` (0 `mod` x)
+gcd x y  =  0
+
+gcd 0 x  =  0 `mod` (x `mod` x)
+gcd x y  =  x
+
+gcd 0 x  =  0 `mod` (x `mod` x)
+gcd x y  =  y
+
+gcd 0 x  =  0 `mod` (x `mod` x)
+gcd x y  =  0
+
+gcd 0 x  =  0 `mod` (x `mod` 0)
+gcd x y  =  x
+
+gcd 0 x  =  0 `mod` (x `mod` 0)
+gcd x y  =  y
+
+gcd 0 x  =  0 `mod` (x `mod` 0)
+gcd x y  =  0
+
+gcd 0 x  =  0 `mod` (0 `mod` x)
+gcd x y  =  x
+
+gcd 0 x  =  0 `mod` (0 `mod` x)
+gcd x y  =  y
+
+gcd 0 x  =  0 `mod` (0 `mod` x)
+gcd x y  =  0
+
+gcd 0 x  =  (x `mod` x) `mod` x
+gcd x y  =  x
+
+gcd 0 x  =  (x `mod` x) `mod` x
+gcd x y  =  y
+
+gcd 0 x  =  (x `mod` x) `mod` x
+gcd x y  =  0
+
+gcd 0 x  =  (x `mod` x) `mod` 0
+gcd x y  =  x
+
+gcd 0 x  =  (x `mod` x) `mod` 0
+gcd x y  =  y
+
+gcd 0 x  =  (x `mod` x) `mod` 0
+gcd x y  =  0
+
+gcd 0 x  =  (x `mod` 0) `mod` x
+gcd x y  =  x
+
+gcd 0 x  =  (x `mod` 0) `mod` x
+gcd x y  =  y
+
+gcd 0 x  =  (x `mod` 0) `mod` x
+gcd x y  =  0
+
+gcd 0 x  =  (x `mod` 0) `mod` 0
+gcd x y  =  x
+
+gcd 0 x  =  (x `mod` 0) `mod` 0
+gcd x y  =  y
+
+gcd 0 x  =  (x `mod` 0) `mod` 0
+gcd x y  =  0
+
+gcd 0 x  =  (0 `mod` x) `mod` x
+gcd x y  =  x
+
+gcd 0 x  =  (0 `mod` x) `mod` x
+gcd x y  =  y
+
+gcd 0 x  =  (0 `mod` x) `mod` x
+gcd x y  =  0
+
+gcd 0 x  =  (0 `mod` x) `mod` 0
+gcd x y  =  x
+
+gcd 0 x  =  (0 `mod` x) `mod` 0
+gcd x y  =  y
+
+gcd 0 x  =  (0 `mod` x) `mod` 0
+gcd x y  =  0
+
+gcd x 0  =  x
+gcd x y  =  gcd x (x `mod` y)
+
+gcd x 0  =  x
+gcd x y  =  gcd x (y `mod` y)
+
+gcd x 0  =  x
+gcd x y  =  gcd y (x `mod` x)
+
+gcd x 0  =  x
+gcd x y  =  gcd y (x `mod` y)
+
+gcd x 0  =  x
+gcd x y  =  gcd y (y `mod` x)
+
+gcd x 0  =  x
+gcd x y  =  gcd y (y `mod` y)
+
+gcd x 0  =  x
+gcd x y  =  gcd 0 (x `mod` y)
+
+gcd x 0  =  x
+gcd x y  =  gcd 0 (y `mod` y)
+
+gcd x 0  =  x
+gcd x y  =  gcd (x `mod` x) x
+
+gcd x 0  =  x
+gcd x y  =  gcd (x `mod` x) y
+
+gcd x 0  =  x
+gcd x y  =  gcd (x `mod` y) x
+
+gcd x 0  =  x
+gcd x y  =  gcd (y `mod` x) x
+
+gcd x 0  =  x
+gcd x y  =  gcd (y `mod` x) y
+
+gcd x 0  =  x
+gcd x y  =  gcd (y `mod` y) x
+
+gcd 0 x  =  x
+gcd x y  =  gcd x (x `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  gcd x (y `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  gcd y (x `mod` x)
+
+gcd 0 x  =  x
+gcd x y  =  gcd y (x `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  gcd y (y `mod` x)
+
+gcd 0 x  =  x
+gcd x y  =  gcd y (y `mod` y)
+
+gcd 0 x  =  x
+gcd x y  =  gcd (x `mod` x) x
+
+gcd 0 x  =  x
+gcd x y  =  gcd (x `mod` x) y
+
+gcd 0 x  =  x
+gcd x y  =  gcd (x `mod` x) 0
+
+gcd 0 x  =  x
+gcd x y  =  gcd (x `mod` y) x
+
+gcd 0 x  =  x
+gcd x y  =  gcd (y `mod` x) x
+
+gcd 0 x  =  x
+gcd x y  =  gcd (y `mod` x) y
+
+gcd 0 x  =  x
+gcd x y  =  gcd (y `mod` x) 0
+
+gcd 0 x  =  x
+gcd x y  =  gcd (y `mod` y) x
 
 
 
diff --git a/bench/carry-on.hs b/bench/carry-on.hs
--- a/bench/carry-on.hs
+++ b/bench/carry-on.hs
@@ -15,8 +15,8 @@
 main  =  do
   -- carry on Conjuring larger implementations
   conjure "factorial n" factorial
-    [ unfun (0::Int)
-    , unfun (1::Int)
+    [ con (0::Int)
+    , con (1::Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
diff --git a/bench/carry-on.txt b/bench/carry-on.txt
--- a/bench/carry-on.txt
+++ b/bench/carry-on.txt
@@ -2,46 +2,46 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 7 candidates of size 3
--- 8 candidates of size 4
--- 28 candidates of size 5
--- 35 candidates of size 6
--- 167 candidates of size 7
--- tested 95 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 23 candidates of size 5
+-- 0 candidates of size 6
+-- 147 candidates of size 7
+-- tested 173 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
--- 203 candidates of size 8
--- tested 254 candidates
+-- 8 candidates of size 8
+-- tested 182 candidates
 factorial 1  =  1
 factorial x  =  x * factorial (x - 1)
 
--- 1048 candidates of size 9
--- tested 547 candidates
+-- 941 candidates of size 9
+-- tested 1115 candidates
 factorial 0  =  0
 factorial 1  =  1
 factorial x  =  x * factorial (x - 1)
 
--- tested 555 candidates
+-- tested 1123 candidates
 factorial 0  =  1
 factorial 1  =  1
 factorial x  =  x * factorial (x - 1)
 
--- 1299 candidates of size 10
--- 7200 candidates of size 11
--- tested 3213 candidates
+-- 49 candidates of size 10
+-- 6490 candidates of size 11
+-- tested 7239 candidates
 factorial 0  =  1
 factorial x  =  x + x * (factorial (x - 1) - 1)
 
--- tested 3393 candidates
+-- tested 7421 candidates
 factorial 0  =  1
 factorial x  =  x - x * (1 - factorial (x - 1))
 
--- tested 3516 candidates
+-- tested 7544 candidates
 factorial 0  =  1
 factorial x  =  (0 - x) * (0 - factorial (x - 1))
 
--- tested 10001 candidates
+-- tested 7667 candidates
 factorial n  =  undefined  -- search exhausted
 
diff --git a/bench/erroneous.hs b/bench/erroneous.hs
--- a/bench/erroneous.hs
+++ b/bench/erroneous.hs
@@ -58,44 +58,44 @@
   let n = 6
 
   printErroneousCandidates (n+1) "foo" (undefined :: Int -> Int)
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , unfun (2 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , con (2 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
 
   printErroneousCandidates n "?" (undefined :: Int -> Int -> Int)
-    [ unfun (0 :: Int)
+    [ con (0 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "dec" (subtract 1 :: Int -> Int)
     ]
 
   printErroneousCandidates (n+1) "goo" (undefined :: [Int] -> [Int])
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   printErroneousCandidates n "??" (undefined :: [Int] -> [Int] -> [Int])
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   printErroneousCandidates n "ton" (undefined :: Bool -> Bool)
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "not" not
     ]
 
   printErroneousCandidates n "&|" (undefined :: Bool -> Bool -> Bool)
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "not" not
diff --git a/bench/erroneous.txt b/bench/erroneous.txt
--- a/bench/erroneous.txt
+++ b/bench/erroneous.txt
@@ -138,6 +138,30 @@
 -- 1 ? 0  =  bottom  -- and 16 other errors
 
 x ? 0  =  x
+x ? y  =  dec (dec x ? y)
+-- 0 ? 1  =  bottom  -- and 16 other errors
+
+x ? 0  =  0
+x ? y  =  dec (dec x ? y)
+-- 0 ? 1  =  bottom  -- and 16 other errors
+
+x ? 0  =  dec x
+x ? y  =  dec x ? y
+-- 0 ? 1  =  bottom  -- and 16 other errors
+
+0 ? x  =  x
+x ? y  =  dec (x ? dec y)
+-- 1 ? 0  =  bottom  -- and 16 other errors
+
+0 ? x  =  0
+x ? y  =  dec (x ? dec y)
+-- 1 ? 0  =  bottom  -- and 16 other errors
+
+0 ? x  =  dec x
+x ? y  =  x ? dec y
+-- 1 ? 0  =  bottom  -- and 16 other errors
+
+x ? 0  =  x
 x ? y  =  x ? dec (dec y)
 -- 0 ? 1  =  bottom  -- and 9 other errors
 
@@ -208,30 +232,6 @@
 0 ? x  =  x
 x ? y  =  dec (dec y) ? x
 -- 1 ? 0  =  bottom  -- and 6 other errors
-
-x ? 0  =  x
-x ? y  =  dec (dec x ? y)
--- 0 ? 1  =  bottom  -- and 16 other errors
-
-x ? 0  =  0
-x ? y  =  dec (dec x ? y)
--- 0 ? 1  =  bottom  -- and 16 other errors
-
-x ? 0  =  dec x
-x ? y  =  dec x ? y
--- 0 ? 1  =  bottom  -- and 16 other errors
-
-0 ? x  =  x
-x ? y  =  dec (x ? dec y)
--- 1 ? 0  =  bottom  -- and 16 other errors
-
-0 ? x  =  0
-x ? y  =  dec (x ? dec y)
--- 1 ? 0  =  bottom  -- and 16 other errors
-
-0 ? x  =  dec x
-x ? y  =  x ? dec y
--- 1 ? 0  =  bottom  -- and 16 other errors
 
 
 Erroneous candidates for: goo :: [Int] -> [Int]
diff --git a/bench/gps.hs b/bench/gps.hs
--- a/bench/gps.hs
+++ b/bench/gps.hs
@@ -44,10 +44,10 @@
 
 gps1c30p :: IO ()
 gps1c30p  =  conjure "gps1" gps1p
-  [ unfun (0 :: Float)
-  , unfun (1 :: Float)
-  , unfun (1/2 :: Float)
-  , unfun (-1 :: Float)
+  [ con (0 :: Float)
+  , con (1 :: Float)
+  , con (1/2 :: Float)
+  , con (-1 :: Float)
   , fun "+" ((+) :: Float -> Float -> Float)
   , fun "*" ((*) :: Float -> Float -> Float)
   , fun "-" ((-) :: Float -> Float -> Float)
@@ -56,9 +56,9 @@
   , fun "id" (id :: Float -> Float)
   , fun "fromIntegral" (fromIntegral :: Int -> Float)
 
-  , unfun (0 :: Int)
-  , unfun (1 :: Int)
-  , unfun (-1 :: Int)
+  , con (0 :: Int)
+  , con (1 :: Int)
+  , con (-1 :: Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
   , fun "-" ((-) :: Int -> Int -> Int)
@@ -71,8 +71,8 @@
   , fun "round" (round :: Float -> Int)
   , fun "truncate" (truncate :: Float -> Int)
 
-  , unfun False
-  , unfun True
+  , con False
+  , con True
   , fun "&&" (&&)
   , fun "||" (||)
   , fun "not" not
@@ -95,17 +95,16 @@
 
 gps2c :: IO ()
 gps2c  =  conjure "gps2" gps2p
-  [ unfun "small"
-  , unfun "large"
-  , unfun (1000 :: Int)
-  , unfun (2000 :: Int)
+  [ con "small"
+  , con "large"
+  , con (1000 :: Int)
+  , con (2000 :: Int)
   , fun "Just" (Just :: String -> Maybe String)
   , fun "Nothing" (Nothing :: Maybe String)
   , fun "<=" ((<=) :: Int -> Int -> Bool)
   , fun "<" ((<) :: Int -> Int -> Bool)
-  , iif (undefined :: Maybe String)
+  , guard
   , maxTests 5040
-  , maxSize 30
   ]
 
 
@@ -117,27 +116,28 @@
 gps3g1 start end step  =  enumFromThenTo start (step+start) (end-1)
 
 gps3g2 :: Int -> Int -> Int -> [Int]
-gps3g2 start end step  =  if start < end
-                          then start : gps3g2 (start+step) end step
-                          else []
+gps3g2 start end step
+  | start < end  =  start : gps3g2 (start+step) end step -- 11
+  | otherwise    =  [] -- 12
 
 gps3c :: IO ()
 gps3c  =  do
   conjure "gps3" gps3p
-    [ unfun (1 :: Int)
+    [ con (1 :: Int)
     , fun "enumFromThenTo" ((\x y z -> take 720 $ enumFromThenTo x y z) :: Int -> Int -> Int -> [Int])
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
 
   -- not possible, no recursive descent
-  conjure "gps3" gps3p
-    [ unfun ([] :: [Int])
+  conjure "gps3_alt" gps3p
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "<" ((<) :: Int -> Int -> Bool)
-    , iif (undefined :: [Int])
-    , maxSize 8
+    , guard
+    , dontRequireDescent
+    -- TODO: shouldn't a solution appear here?
     ]
 
 
@@ -170,27 +170,43 @@
 gps5p " "  =  " "
 gps5p "!"  =  "!!!"
 gps5p "aa"  =  "aaaa"
+gps5p " a"  =  " aa"
+gps5p "!a"  =  "!!!aa"
 
 gps5g :: String -> String
-gps5g []  =  []
+gps5g ""  =  ""
 gps5g (c:cs)
   | isLetter c  =  c:c:gps5g cs
   | c == '!'    =  c:c:c:gps5g cs
   | otherwise   =  c:gps5g cs
 
 gps5c :: IO ()
-gps5c  =  conjure "gps5" gps5p -- can't find
-  [ unfun ""
+gps5c  =  conjure "gps5" gps5p
+  [ con ""
   , fun ":" ((:) :: Char -> String -> String)
-  , unfun '!'
+  , con '!'
   , fun "==" ((==) :: Char -> Char -> Bool)
   , fun "isLetter" (isLetter :: Char -> Bool)
-  , iif (undefined :: String -> String)
-  , maxSize 6
+  , guard
+  -- BENCHMARK: increase to 26 to find
+  , maxSize 12 -- 26
   ]
+  -- found (lapmatrud unplugged):
+  -- -- 65.5s, 10856 candidates of size 26
+  -- -- 65.5s, tested 20317 candidates
+  -- gps5 ""  =  ""
+  -- gps5 (c:cs)
+  --   | isLetter c  =  c:c:gps5 cs
+  --   | c == '!'  =  c:c:c:gps5 cs
+  --   | otherwise  =  c:gps5 cs
 
 
+
 -- GPS Benchmark #6 -- Collatz/Hailstone numbers --
+-- Given an integer, find the number of terms in the Collatz (hailstone)
+-- sequence starting from that integer.
+-- NOTE: The sequence is actually always infinite,
+-- so I assume it is the count until reaching 1.
 
 gps6p :: Int -> Int
 gps6p 1  =  1
@@ -212,26 +228,71 @@
                         then n `div` 2  -- 10
                         else 3*n + 1)   -- 15
 
--- This one is out of reach performance wise:
--- Speculate hangs with this background.
--- Removing three or setting maxEqSize to 4 makes it unhang.
--- But a size of 15 or 17 is simplyl out of our reach.
+nextCollatz' :: Int -> Int
+nextCollatz' 1  =  4
+nextCollatz' 2  =  1
+nextCollatz' 3  =  10
+nextCollatz' 4  =  2
+nextCollatz' 5  =  16
+nextCollatz' 6  =  3
+
+nextCollatz :: Int -> Int
+nextCollatz n
+  | even n     =  n `div` 2
+  | otherwise  =  3*n + 1
+
 gps6c :: IO ()
-gps6c  =  conjure "gps6" gps6p
-  [ unfun (1 :: Int)
-  , unfun (2 :: Int)
-  , unfun (3 :: Int)
-  , fun "+" ((+) :: Int -> Int -> Int)
-  , fun "*" ((*) :: Int -> Int -> Int)
-  , fun "`div`" (div :: Int -> Int -> Int)
-  , fun "even" (even :: Int -> Bool)
-  , iif (undefined :: Int)
-  , maxSize 6
-  , maxEquationSize 3
-  ]
+gps6c  =  do
+  -- This one is out of reach performance wise:
+  -- Speculate hangs with this background.
+  -- Removing three or setting maxEqSize to 4 makes it unhang.
+  -- But a size of 15 or 17 is simplyl out of our reach.
+  conjure "gps6direct" gps6p
+    [ con (1 :: Int)
+    , con (2 :: Int)
+    , con (3 :: Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun "*" ((*) :: Int -> Int -> Int)
+    , fun "`div`" (div :: Int -> Int -> Int)
+    , fun "even" (even :: Int -> Bool)
+    , iif (undefined :: Int)
+    , maxSize 6
+    , maxEquationSize 3  -- degenerate case in Speculate
+    ]
 
+  conjure "gps6step" gps6p
+    [ con (1 :: Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun "nextCollatz" nextCollatz
+    , dontRequireDescent
+    ]
 
+  conjure "nextCollatz" nextCollatz
+    [ con (1 :: Int)
+    , con (2 :: Int)
+    , con (3 :: Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun "*" ((*) :: Int -> Int -> Int)
+    , fun "`div`" (div :: Int -> Int -> Int)
+    , fun "even" (even :: Int -> Bool)
+    , guard
+    , target 720720
+    , maxEquationSize 3  -- degenerate case in Speculate
+    -- BENCHMARK: set maxSize 11
+    , maxSize 6 -- 11
+    ]
+  -- -- on lapmatrud (2025-08), found after
+  -- -- 18.5s, 754952 candidates of size 11
+  -- -- 19.4s, tested 568616 candidates
+  -- nextCollatz x
+  --   | even x  =  x `div` 2
+  --   | otherwise  =  1 + x * 3
+
+
 -- GPS Benchmark #7 -- Replace Space with Newline (P 4.3)
+-- Given a string input, print the string, replacing spaces with newlines.
+-- Also, return the integer count of the non-whitespace characters.
+-- The input string will not have tabs or newlines.
 
 gps7p :: String -> (String, Int)
 gps7p "a"  =  ("a", 1)
@@ -301,7 +362,7 @@
 
 gps9c :: IO ()
 gps9c  =  conjure "gps9" gps9p
-  [ unfun (1 :: Int)
+  [ con (1 :: Int)
   , fun "map" (map :: (Int -> Int) -> [Int] -> [Int])
   , fun "filter" (filter :: (Int -> Bool) -> [Int] -> [Int])
   , fun ".." (enumFromTo :: Int -> Int -> [Int])
@@ -353,31 +414,31 @@
 gps10c :: IO ()
 gps10c  =  do
   conjure "wallisNext" wallisNextP
-    [ unfun (1 :: Integer)
-    , unfun (2 :: Integer)
+    [ con (1 :: Integer)
+    , con (2 :: Integer)
     , fun "+" ((+) :: Integer -> Integer -> Integer)
     , fun "*" ((*) :: Integer -> Integer -> Integer)
     , fun "%" ((%) :: Integer -> Integer -> Rational)
     , fun "<" ((<) :: Integer -> Integer -> Bool)
 --  , fun "numerator" (numerator :: Rational -> Integer)
 --  , fun "denominator" (denominator :: Rational -> Integer)
-    , iif (undefined :: Rational)
+    , guard
     ]
 
   -- simplified background
   conjure "wallisNext" wallisNextP
-    [ unfun (0 :: Integer)
-    , unfun (1 :: Integer)
+    [ con (0 :: Integer)
+    , con (1 :: Integer)
     , fun "+" ((+) :: Integer -> Integer -> Integer)
     , fun "*" ((*) :: Integer -> Integer -> Integer)
     , fun "%" ((%) :: Integer -> Integer -> Rational)
     ]
 
   conjure "gps10" gps10p
-    [ unfun (2 :: Integer)
-    , unfun (3 :: Integer)
+    [ con (2 :: Integer)
+    , con (3 :: Integer)
     , fun "%" ((%) :: Integer -> Integer -> Rational)
---  , unfun (2/3 :: Rational)
+--  , con (2/3 :: Rational)
     , fun "product"    (product :: [Rational] -> Rational)
     , fun "take"       (take :: Int -> [Rational] -> [Rational])
     , fun "iterate"    ((\f -> take 720 . iterate f) :: (Rational -> Rational) -> Rational -> [Rational])
@@ -409,7 +470,7 @@
     ]
 
   conjure "gps11" gps11p
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     , fun "length"  (length :: String -> Int)
@@ -438,8 +499,8 @@
     , fun "fromJust"  (fromJust :: Maybe Int -> Int)
     , fun "-"         ((-) :: Int -> Int -> Int)
     , fun "=="        ((==) :: Int -> Int -> Bool)
-    , unfun (0 :: Int)
-    , unfun (1 :: Int)
+    , con (0 :: Int)
+    , con (1 :: Int)
     , maxSize 11
     ]
 
@@ -496,9 +557,9 @@
 gps14c :: IO ()
 gps14c  =  do
   conjure "odd" odd'
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , unfun (2 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , con (2 :: Int)
     , fun "`mod`" (mod :: Int -> Int -> Int)
     , fun "/=" ((/=) :: Int -> Int -> Bool)
     ]
@@ -513,13 +574,13 @@
   -- gps14 []  =  0
   -- gps14 (x:xs)  =  x `mod` 2 + gps14 xs
   conjure "gps14" gps14p
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , unfun (2 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , con (2 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "`mod`" (mod :: Int -> Int -> Int)
     , fun "==" ((==) :: Int -> Int -> Bool)
-    , iif (undefined :: Int)
+    , guard
     ]
 
 
@@ -577,8 +638,8 @@
 
 gps17c :: IO ()
 gps17c  =  conjure "gps17" gps17p
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
+  [ con (0 :: Int)
+  , con (1 :: Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
   , fun "-" ((-) :: Int -> Int -> Int)
@@ -602,7 +663,7 @@
 gps18c :: IO ()
 gps18c  =  do
   conjure "gps18" gps18p
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     ]
@@ -692,19 +753,19 @@
 gps20c :: IO ()
 gps20c  =  do
   conjure "isVowel" isVowel'
-    [ unfun 'a'
-    , unfun 'e'
-    , unfun 'i'
-    , unfun 'o'
-    , unfun 'u'
-    , unfun 'y'
-    , unfun True
-    , unfun False
+    [ con 'a'
+    , con 'e'
+    , con 'i'
+    , con 'o'
+    , con 'u'
+    , con 'y'
+    , con True
+    , con False
     ]
 
   conjureFromSpec "pig1" pig1Spec
-    [ unfun "ay"
-    , iif (undefined :: String)
+    [ con "ay"
+    , guard
     , fun "isVowel" isVowel
     , fun "++" ((++) :: String -> String -> String)
     , fun ":" ((:) :: Char -> String -> String)
@@ -727,6 +788,7 @@
 gps21p [-1]  =  [0]
 gps21p [1,-1]  =  [1,0]
 gps21p [-1,1]  =  [0,1]
+gps21p [-1,-1]  =  [0,0]
 
 gps21g :: [Int] -> [Int]
 gps21g []  =  []
@@ -734,11 +796,11 @@
 
 gps21c :: IO ()
 gps21c  =  conjure "gps21" gps21p
-  [ unfun ([] :: [Int])
-  , unfun (0 :: Int)
+  [ con ([] :: [Int])
+  , con (0 :: Int)
   , fun ":" ((:) :: Int -> [Int] -> [Int])
   , fun "<" ((<) :: Int -> Int -> Bool)
-  , iif (undefined :: Int)
+  , guard
   ]
 
 
@@ -778,8 +840,16 @@
 
 gps22c :: IO ()
 gps22c  =  do
+  conjure "scrabble1" scrabble1 $
+    [ con (1 :: Int)
+    -- comment-out the following to find function
+    -- at size 137 after 1025 candidates in 6.0s
+    -- limited here for faster runtimes
+    , maxSize 13
+    ] ++ map con "dgbcmpfhvwykjxqz"
+
   conjureFromSpec "gps22" gps22s
-    [ unfun (0 :: Int)
+    [ con (0 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "map" (map :: (Int -> Int) -> [Int] -> [Int])
     , fun "scrabble1" scrabble1
@@ -808,14 +878,19 @@
 
 gps24c :: IO ()
 gps24c  =  conjure "gps24" gps24p
-  [ unfun ' '
-  , unfun (64 :: Int)
+  [ con ' '
+  , con (64 :: Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "`mod`" (mod :: Int -> Int -> Int)
   , fun "sum" (sum :: [Int] -> Int)
   , fun "ord" ord
   , fun "chr" chr
   , fun "map" (map :: (Char -> Int) -> String -> [Int])
+
+  -- The following flag is here so behaviour is consistent between different
+  -- GHC versions (8.8 and later).  It makes no significant difference in
+  -- runtime for this example.
+  , maxEarlyTests 0
   ]
 
 
@@ -834,12 +909,12 @@
 
 -- out of reach performance-wise
 gps25c :: IO ()
-gps25c  =  conjure "gps25" gps25p $ take 0
-  [ unfun (0 :: Int)
-  , unfun (10 :: Int)
-  , unfun ([] :: [Int])
+gps25c  =  conjure "gps25" gps25p
+  [ con (0 :: Int)
+  , con (10 :: Int)
+  , con ([] :: [Int])
   , fun ":" ((:) :: Int -> [Int] -> [Int])
-  , iif (undefined :: [Int])
+  , guard
   , fun "abs" (abs :: Int -> Int)
   , fun "<" ((<) :: Int -> Int -> Bool)
   , fun "rem" (rem :: Int -> Int -> Int)
@@ -858,48 +933,57 @@
 
 gps26g :: Int -> Int -> Int -> Int -> Int -> Char
 gps26g a b c d x
-  | x >= a     =  'A'
-  | x >= b     =  'B'
-  | x >= c     =  'C'
-  | x >= d     =  'D'
-  | otherwise  =  'F'
+  | x >= a     =  'A'  -- 5
+  | x >= b     =  'B'  -- 10
+  | x >= c     =  'C'  -- 15
+  | x >= d     =  'D'  -- 20
+  | otherwise  =  'F'  -- 21
 
--- out of reach performance-wise
+-- out of reach performance-wise, OOM at size 21, see:
+-- -- 20.6s, 4000000 candidates of size 16
+-- -- 38.2s, 0 candidates of size 20
+-- gps: out of memory
+
 gps26c :: IO ()
 gps26c  =  conjure "gps26" gps26p
-  [ unfun 'A'
-  , unfun 'B'
-  , unfun 'C'
-  , unfun 'D'
-  , unfun 'F'
-  , iif (undefined :: Char)
+  [ con 'A'
+  , con 'B'
+  , con 'C'
+  , con 'D'
+  , con 'F'
+  , guard
   , fun ">=" ((>=) :: Int -> Int -> Bool)
-  , maxSize 2
   ]
 
 
 -- GPS Benchmark #27 -- Median --
+-- Given three integers, print their median.
 gps27p :: Int -> Int -> Int -> Int
 gps27p 0 1 2  =  1
+gps27p 0 2 1  =  1
+gps27p 2 3 1  =  2
 gps27p 1 0 2  =  1
-gps27p (-1) 1 0  =  0
+gps27p 4 3 1  =  3
+gps27p 4 1 3  =  3
 
 gps27g :: Int -> Int -> Int -> Int
 gps27g x y z
-  | y < x && x < z  =  x  -- 8
-  | x < y && y < z  =  y  -- 16
-  | otherwise       =  z  -- 17
--- Conjure found a smaller implementation!
+  | y <= x && x <= z || z <= x && x <= y  =  x  -- 16
+  | x <= y && y <= z || z <= y && y <= x  =  y  -- 32
+  | otherwise                             =  z  -- 33
 
 gps27c :: IO ()
 gps27c  =  do
-  conjure "gps27" gps27p
-    [ fun "<" ((<) :: Int -> Int -> Bool)
+  -- simply unreachable performance-wise
+  -- it gets OOM at size 25 after >83s.
+  conjure "gps27_median" gps27p
+    [ fun "<=" ((<=) :: Int -> Int -> Bool)
     , fun "&&" (&&)
-    , iif (undefined :: Int)
+    , fun "||" (||)
+    , guard
     ]
 
-  conjure "gps27b" gps27p
+  conjure "gps27b_median" gps27p
     [ fun "min" (min :: Int -> Int -> Int)
     , fun "max" (max :: Int -> Int -> Int)
     ]
@@ -938,10 +1022,10 @@
 
 gps29c :: IO ()
 gps29c  =  conjureFromSpec "gps29" gps29s
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
+  [ con (0 :: Int)
+  , con (1 :: Int)
   , fun "+" ((+) :: Int->Int->Int)
-  , iif (undefined :: Int)
+  , guard
   , fun "isVowel" isVowel
   ]
 
diff --git a/bench/gps.txt b/bench/gps.txt
--- a/bench/gps.txt
+++ b/bench/gps.txt
@@ -6,28 +6,29 @@
 -- 1 candidates of size 3
 -- 2 candidates of size 4
 -- tested 4 candidates
-gps1 x y  =  fromIntegral x + y
+gps1 x y  =  y + fromIntegral x
 
 gps2 :: Int -> Maybe [Char]
 -- testing 6 combinations of argument values
 -- pruning with 9/17 rules
 -- 1 candidates of size 1
 -- 2 candidates of size 2
--- 3 candidates of size 3
--- 2 candidates of size 4
--- 2 candidates of size 5
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
 -- 0 candidates of size 6
 -- 32 candidates of size 7
--- 32 candidates of size 8
--- 48 candidates of size 9
--- 32 candidates of size 10
--- 16 candidates of size 11
--- 512 candidates of size 12
--- 1408 candidates of size 13
--- tested 1171 candidates
-gps2 x  =  if 2000 <= x
-           then Just "large"
-           else if x < 1000 then Just "small" else Nothing
+-- 16 candidates of size 8
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 0 candidates of size 11
+-- 256 candidates of size 12
+-- 640 candidates of size 13
+-- tested 664 candidates
+gps2 x
+  | 2000 <= x  =  Just "large"
+  | 1000 <= x  =  Nothing
+  | otherwise  =  Just "small"
 
 gps3 :: Int -> Int -> Int -> [Int]
 -- testing 2 combinations of argument values
@@ -39,11 +40,11 @@
 -- 0 candidates of size 5
 -- 1248 candidates of size 6
 -- 0 candidates of size 7
--- 17008 candidates of size 8
--- tested 12358 candidates
+-- 13680 candidates of size 8
+-- tested 3238 candidates
 gps3 x y z  =  enumFromThenTo x (x + z) (y - 1)
 
-gps3 :: Int -> Int -> Int -> [Int]
+gps3_alt :: Int -> Int -> Int -> [Int]
 -- testing 2 combinations of argument values
 -- pruning with 6/18 rules
 -- 1 candidates of size 1
@@ -54,8 +55,13 @@
 -- 0 candidates of size 6
 -- 81 candidates of size 7
 -- 36 candidates of size 8
--- tested 136 candidates
-gps3  =  undefined  -- search exhausted
+-- 441 candidates of size 9
+-- 432 candidates of size 10
+-- 2403 candidates of size 11
+-- 3636 candidates of size 12
+-- 13311 candidates of size 13
+-- tested 20359 candidates
+gps3_alt  =  undefined  -- search exhausted
 
 gps4 :: [Char] -> [Char] -> [Char] -> Bool
 -- testing 9 combinations of argument values
@@ -75,29 +81,60 @@
 gps4 cs ds es  =  length cs < length ds && length ds < length es
 
 gps5 :: [Char] -> [Char]
--- testing 5 combinations of argument values
--- pruning with 2/3 rules
+-- testing 7 combinations of argument values
+-- pruning with 5/6 rules
 -- 2 candidates of size 1
 -- 0 candidates of size 2
 -- 2 candidates of size 3
 -- 0 candidates of size 4
--- 4 candidates of size 5
+-- 3 candidates of size 5
 -- 0 candidates of size 6
--- tested 8 candidates
+-- 3 candidates of size 7
+-- 0 candidates of size 8
+-- 3 candidates of size 9
+-- 2 candidates of size 10
+-- 6 candidates of size 11
+-- 5 candidates of size 12
+-- tested 26 candidates
 gps5  =  undefined  -- search exhausted
 
-gps6 :: Int -> Int
+gps6direct :: Int -> Int
 -- testing 9 combinations of argument values
 -- pruning with 16/18 rules
 -- 4 candidates of size 1
--- 2 candidates of size 2
--- 14 candidates of size 3
--- 14 candidates of size 4
--- 186 candidates of size 5
--- 165 candidates of size 6
--- tested 385 candidates
-gps6  =  undefined  -- search exhausted
+-- 0 candidates of size 2
+-- 12 candidates of size 3
+-- 0 candidates of size 4
+-- 172 candidates of size 5
+-- 0 candidates of size 6
+-- tested 188 candidates
+gps6direct  =  undefined  -- search exhausted
 
+gps6step :: Int -> Int
+-- testing 9 combinations of argument values
+-- pruning with 4/8 rules
+-- 2 candidates of size 1
+-- 1 candidates of size 2
+-- 3 candidates of size 3
+-- 4 candidates of size 4
+-- 12 candidates of size 5
+-- 27 candidates of size 6
+-- tested 46 candidates
+gps6step 1  =  1
+gps6step x  =  1 + gps6step (nextCollatz x)
+
+nextCollatz :: Int -> Int
+-- testing 360 combinations of argument values
+-- pruning with 16/18 rules
+-- 4 candidates of size 1
+-- 0 candidates of size 2
+-- 12 candidates of size 3
+-- 0 candidates of size 4
+-- 172 candidates of size 5
+-- 0 candidates of size 6
+-- tested 188 candidates
+nextCollatz  =  undefined  -- search exhausted
+
 gps7 :: [Char] -> ([Char],Int)
 -- testing 4 combinations of argument values
 -- pruning with 5/10 rules
@@ -112,7 +149,7 @@
 -- 88 candidates of size 9
 -- 201 candidates of size 10
 -- 442 candidates of size 11
--- tested 546 candidates
+-- tested 553 candidates
 gps7 cs  =  (init (unlines (words cs)),length (filter (not . isSpace) cs))
 
 gps8 :: [Char] -> [Char] -> [(Int,Char,Char)]
@@ -135,10 +172,10 @@
 -- 10 candidates of size 5
 -- 21 candidates of size 6
 -- 30 candidates of size 7
--- 77 candidates of size 8
--- 134 candidates of size 9
--- 245 candidates of size 10
--- tested 306 candidates
+-- 69 candidates of size 8
+-- 114 candidates of size 9
+-- 212 candidates of size 10
+-- tested 278 candidates
 gps9 x  =  filter even (filter (x >) (map sq [1..x]))
 
 wallisNext :: Ratio Integer -> Ratio Integer
@@ -147,12 +184,12 @@
 -- 1 candidates of size 1
 -- 0 candidates of size 2
 -- 3 candidates of size 3
--- 0 candidates of size 4
+-- 15 candidates of size 4
 -- 4 candidates of size 5
--- 0 candidates of size 6
+-- 86 candidates of size 6
 -- 5 candidates of size 7
--- 1 candidates of size 8
--- tested 14 candidates
+-- 513 candidates of size 8
+-- tested 368 candidates
 wallisNext (x % y)  =  (y + 1) % (x + 1)
 
 wallisNext :: Ratio Integer -> Ratio Integer
@@ -161,12 +198,12 @@
 -- 1 candidates of size 1
 -- 0 candidates of size 2
 -- 4 candidates of size 3
--- 0 candidates of size 4
+-- 16 candidates of size 4
 -- 3 candidates of size 5
--- 0 candidates of size 6
+-- 71 candidates of size 6
 -- 5 candidates of size 7
--- 1 candidates of size 8
--- tested 14 candidates
+-- 393 candidates of size 8
+-- tested 295 candidates
 wallisNext (x % y)  =  (y + 1) % (x + 1)
 
 gps10 :: Int -> Ratio Integer
@@ -201,10 +238,10 @@
 -- 0 candidates of size 3
 -- 0 candidates of size 4
 -- 0 candidates of size 5
--- 2 candidates of size 6
+-- 1 candidates of size 6
 -- 0 candidates of size 7
 -- 1 candidates of size 8
--- tested 4 candidates
+-- tested 3 candidates
 gps11 []  =  []
 gps11 (cs:css)  =  gps11 css ++ [length cs]
 
@@ -222,8 +259,8 @@
 -- 416 candidates of size 9
 -- 956 candidates of size 10
 -- 3073 candidates of size 11
--- tested 4404 candidates
-gps12 xs  =  (length xs - fromJust (findIndex (0 ==) (reverse xs))) - 1
+-- tested 1713 candidates
+gps12 xs  =  (length xs - 1) - fromJust (findIndex (0 ==) (reverse xs))
 
 gps13 :: [Ratio Integer] -> Ratio Integer
 -- testing 3 combinations of argument values
@@ -234,9 +271,9 @@
 -- 2 candidates of size 4
 -- 9 candidates of size 5
 -- 12 candidates of size 6
--- 67 candidates of size 7
--- 97 candidates of size 8
--- tested 179 candidates
+-- 63 candidates of size 7
+-- 95 candidates of size 8
+-- tested 106 candidates
 gps13 qs  =  foldr (+) 0 qs / fromIntegral (length qs)
 
 odd :: Int -> Bool
@@ -245,9 +282,9 @@
 -- 0 candidates of size 1
 -- 0 candidates of size 2
 -- 3 candidates of size 3
--- 2 candidates of size 4
--- 37 candidates of size 5
--- tested 17 candidates
+-- 0 candidates of size 4
+-- 35 candidates of size 5
+-- tested 15 candidates
 odd x  =  0 /= x `mod` 2
 
 gps14 :: [Int] -> Int
@@ -270,7 +307,7 @@
 -- 30 candidates of size 5
 -- 6 candidates of size 6
 -- 345 candidates of size 7
--- tested 83 candidates
+-- tested 46 candidates
 gps14 []  =  0
 gps14 (x:xs)  =  x + gps14 xs `mod` 2
 
@@ -299,15 +336,15 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 7 candidates of size 3
--- 8 candidates of size 4
--- 28 candidates of size 5
--- 35 candidates of size 6
--- 167 candidates of size 7
--- 203 candidates of size 8
--- 1048 candidates of size 9
--- tested 466 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 23 candidates of size 5
+-- 0 candidates of size 6
+-- 147 candidates of size 7
+-- 8 candidates of size 8
+-- 941 candidates of size 9
+-- tested 1032 candidates
 gps17 0  =  0
 gps17 x  =  x * x + gps17 (x - 1)
 
@@ -319,11 +356,11 @@
 -- 0 candidates of size 3
 -- 10 candidates of size 4
 -- 25 candidates of size 5
--- 34 candidates of size 6
--- 138 candidates of size 7
--- 126 candidates of size 8
--- 743 candidates of size 9
--- tested 767 candidates
+-- 24 candidates of size 6
+-- 114 candidates of size 7
+-- 72 candidates of size 8
+-- 481 candidates of size 9
+-- tested 250 candidates
 gps18 [] xs  =  xs
 gps18 (x:xs) []  =  xs
 gps18 (x:xs) (y:ys)  =  x + y:gps18 xs ys
@@ -335,7 +372,7 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 10 candidates of size 4
--- tested 10 candidates
+-- tested 4 candidates
 gps18  =  zipWith (+)
 
 gps19 :: Int -> [Char] -> [Char]
@@ -350,28 +387,28 @@
 -- testing 12 combinations of argument values
 -- pruning with 0/0 rules
 -- 2 candidates of size 1
--- 1 candidates of size 2
--- 1 candidates of size 3
--- 2 candidates of size 4
--- 2 candidates of size 5
--- 3 candidates of size 6
--- 4 candidates of size 7
--- 4 candidates of size 8
--- 4 candidates of size 9
--- 5 candidates of size 10
--- 5 candidates of size 11
--- 5 candidates of size 12
--- 5 candidates of size 13
--- 4 candidates of size 14
--- 4 candidates of size 15
--- 4 candidates of size 16
--- 3 candidates of size 17
--- 2 candidates of size 18
--- 2 candidates of size 19
--- 1 candidates of size 20
--- 1 candidates of size 21
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 0 candidates of size 6
+-- 0 candidates of size 7
+-- 0 candidates of size 8
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 0 candidates of size 11
+-- 0 candidates of size 12
+-- 0 candidates of size 13
+-- 0 candidates of size 14
+-- 0 candidates of size 15
+-- 0 candidates of size 16
+-- 0 candidates of size 17
+-- 0 candidates of size 18
+-- 0 candidates of size 19
+-- 0 candidates of size 20
+-- 0 candidates of size 21
 -- 1 candidates of size 22
--- tested 65 candidates
+-- tested 3 candidates
 isVowel 'a'  =  True
 isVowel 'e'  =  True
 isVowel 'i'  =  True
@@ -389,18 +426,18 @@
 -- 13 candidates of size 5
 -- 28 candidates of size 6
 -- 46 candidates of size 7
--- 125 candidates of size 8
--- 200 candidates of size 9
--- 625 candidates of size 10
--- 1066 candidates of size 11
--- 3459 candidates of size 12
--- 6361 candidates of size 13
--- 20207 candidates of size 14
--- tested 27628 candidates
+-- 115 candidates of size 8
+-- 176 candidates of size 9
+-- 441 candidates of size 10
+-- 708 candidates of size 11
+-- 1747 candidates of size 12
+-- 2919 candidates of size 13
+-- 6925 candidates of size 14
+-- tested 8943 candidates
 pig1 ""  =  "ay"
-pig1 (c:cs)  =  if isVowel c
-                then (c:cs) ++ "ay"
-                else cs ++ (c:"ay")
+pig1 (c:cs)
+  | isVowel c  =  (c:cs) ++ "ay"
+  | otherwise  =  cs ++ (c:"ay")
 
 gps20c :: [Char] -> [Char]
 -- pruning with 1/1 rules
@@ -413,22 +450,46 @@
 gps20c cs  =  unwords (map pig1 (words cs))
 
 gps21 :: [Int] -> [Int]
--- testing 4 combinations of argument values
+-- testing 5 combinations of argument values
 -- pruning with 4/4 rules
 -- 2 candidates of size 1
 -- 0 candidates of size 2
 -- 2 candidates of size 3
 -- 0 candidates of size 4
--- 4 candidates of size 5
+-- 2 candidates of size 5
 -- 0 candidates of size 6
--- 8 candidates of size 7
+-- 2 candidates of size 7
 -- 0 candidates of size 8
--- 16 candidates of size 9
--- 4 candidates of size 10
--- tested 34 candidates
+-- 2 candidates of size 9
+-- 0 candidates of size 10
+-- 6 candidates of size 11
+-- 0 candidates of size 12
+-- 8 candidates of size 13
+-- tested 19 candidates
 gps21 []  =  []
-gps21 (x:xs)  =  (if x < 0 then 0 else x):gps21 xs
+gps21 (x:xs)
+  | x < 0  =  0:gps21 xs
+  | otherwise  =  x:gps21 xs
 
+scrabble1 :: Char -> Int
+-- testing 97 combinations of argument values
+-- pruning with 0/0 rules
+-- 1 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 0 candidates of size 6
+-- 0 candidates of size 7
+-- 0 candidates of size 8
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 0 candidates of size 11
+-- 0 candidates of size 12
+-- 0 candidates of size 13
+-- tested 1 candidates
+scrabble1  =  undefined  -- search exhausted
+
 gps22 :: [Char] -> Int
 -- pruning with 5/9 rules
 -- 1 candidates of size 1
@@ -448,23 +509,33 @@
 -- testing 4 combinations of argument values
 -- pruning with 15/19 rules
 -- 1 candidates of size 1
--- 1 candidates of size 2
--- 0 candidates of size 3
+-- 2 candidates of size 2
+-- 3 candidates of size 3
 -- 2 candidates of size 4
--- 2 candidates of size 5
--- 2 candidates of size 6
--- 14 candidates of size 7
--- 25 candidates of size 8
--- 71 candidates of size 9
--- 176 candidates of size 10
--- tested 245 candidates
+-- 8 candidates of size 5
+-- 13 candidates of size 6
+-- 30 candidates of size 7
+-- 75 candidates of size 8
+-- 193 candidates of size 9
+-- 469 candidates of size 10
+-- tested 376 candidates
 gps24 cs  =  chr (ord ' ' + sum (map ord cs) `mod` 64)
 
 gps25 :: Int -> [Int]
 -- testing 4 combinations of argument values
--- pruning with 0/0 rules
--- 0 candidates of size 1
--- tested 0 candidates
+-- pruning with 32/37 rules
+-- reasoning produced 1 incorrect properties, please re-run with more tests for faster results
+-- 1 candidates of size 1
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- 1 candidates of size 4
+-- 21 candidates of size 5
+-- 30 candidates of size 6
+-- 259 candidates of size 7
+-- 695 candidates of size 8
+-- 4225 candidates of size 9
+-- 15042 candidates of size 10
+-- tested 20277 candidates
 gps25  =  undefined  -- search exhausted
 
 gps26 :: Int -> Int -> Int -> Int -> Int -> Char
@@ -472,12 +543,21 @@
 -- pruning with 4/4 rules
 -- 5 candidates of size 1
 -- 0 candidates of size 2
--- tested 5 candidates
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 400 candidates of size 6
+-- 0 candidates of size 7
+-- 0 candidates of size 8
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 40000 candidates of size 11
+-- tested 40405 candidates
 gps26  =  undefined  -- search exhausted
 
-gps27 :: Int -> Int -> Int -> Int
--- testing 3 combinations of argument values
--- pruning with 14/18 rules
+gps27_median :: Int -> Int -> Int -> Int
+-- testing 6 combinations of argument values
+-- pruning with 32/42 rules
 -- 3 candidates of size 1
 -- 0 candidates of size 2
 -- 0 candidates of size 3
@@ -487,23 +567,30 @@
 -- 0 candidates of size 7
 -- 0 candidates of size 8
 -- 0 candidates of size 9
--- 90 candidates of size 10
--- 2592 candidates of size 11
--- tested 1489 candidates
-gps27 x y z  =  if x < y
-                then if y < z then y else z
-                else x
+-- 180 candidates of size 10
+-- 648 candidates of size 11
+-- 0 candidates of size 12
+-- 0 candidates of size 13
+-- 1440 candidates of size 14
+-- 6480 candidates of size 15
+-- 11664 candidates of size 16
+-- tested 20451 candidates
+gps27_median  =  undefined  -- search exhausted
 
-gps27b :: Int -> Int -> Int -> Int
--- testing 3 combinations of argument values
+gps27b_median :: Int -> Int -> Int -> Int
+-- testing 6 combinations of argument values
 -- pruning with 20/30 rules
 -- 3 candidates of size 1
 -- 0 candidates of size 2
 -- 6 candidates of size 3
 -- 0 candidates of size 4
 -- 12 candidates of size 5
--- tested 15 candidates
-gps27b x y z  =  min z (max x y)
+-- 0 candidates of size 6
+-- 63 candidates of size 7
+-- 0 candidates of size 8
+-- 342 candidates of size 9
+-- tested 376 candidates
+gps27b_median x y z  =  min (max x y) (max z (min x y))
 
 gps28 :: Int -> Int -> Int -> Int -> Int
 -- testing 5 combinations of argument values
@@ -527,9 +614,12 @@
 -- 2 candidates of size 5
 -- 6 candidates of size 6
 -- 10 candidates of size 7
--- 8 candidates of size 8
--- 24 candidates of size 9
--- tested 36 candidates
+-- 4 candidates of size 8
+-- 12 candidates of size 9
+-- 26 candidates of size 10
+-- tested 55 candidates
 gps29 ""  =  0
-gps29 (c:cs)  =  (if isVowel c then 1 else 0) + gps29 cs
+gps29 (c:cs)
+  | isVowel c  =  1 + gps29 cs
+  | otherwise  =  gps29 cs
 
diff --git a/bench/gps2.hs b/bench/gps2.hs
deleted file mode 100644
--- a/bench/gps2.hs
+++ /dev/null
@@ -1,784 +0,0 @@
--- gps2.hs: General Program Synthesis Benchmark Suite II
---
--- Copyright (C) 2021-2025 Rudy Matela
--- Distributed under the 3-Clause BSD licence (see the file LICENSE).
-{-# LANGUAGE CPP, TemplateHaskell #-}
-import Conjure
-import System.Environment (getArgs)
-
-import Data.List (findIndex, inits)               -- for  #1
-import Data.Char (toUpper)                        -- for  #4
-import Data.Ratio ((%))                           -- for  #7
-import Data.List (findIndices, tails, isPrefixOf) -- for #12
-import Data.Maybe (fromJust)                      -- for #23
-import Test.LeanCheck                             -- for #24
-import Data.Express                               -- for #24
-
-
-gps1p :: [Int] -> Maybe Int
-gps1p [0,-1,2]   =  Just 1
-gps1p [-1,0,1]   =  Just 0
-gps1p [0,-1]     =  Just 1
-gps1p [1,-1,-1]  =  Just 2
-
-gps1g :: [Int] -> Maybe Int
-gps1g xs  =  findIndex (0 >) (map sum (tail (inits xs)))
-
-gps1p2 :: Int -> [Int] -> Int
-gps1p2 0 [0,-1,2]   =  1
-gps1p2 0 [-1,0,1]   =  0
-gps1p2 0 [0,-1]     =  1
-gps1p2 0 [1,-1,-1]  =  2
-gps1p2 0 [0,0,0,-1]  =  3
-gps1p2 0 [1,0,0,-2]  =  3
-
--- efficient gps1, unreachable performance-wise
-gps1g2 :: Int -> [Int] -> Int
-gps1g2 t []  =  undefined -- 1
-gps1g2 t (x:xs)  =  if t + x < 0 -- 7
-                    then 0 -- 8
-                    else 1 + gps1g2 (t + x) xs -- 15
-
-gps1c :: IO ()
-gps1c  =  do
-  conjure "gps1" gps1p
-    [ unfun (0 :: Int)
-    , fun "+" ((+) :: Int -> Int -> Int)
-    , fun ">" ((>) :: Int -> Int -> Bool)
-    , fun "foldr" (foldr :: (Int -> Int -> Int) -> Int -> [Int] -> Int)
-    , fun "sum" (sum :: [Int] -> Int)
-    , fun "findIndex" (findIndex :: (Int -> Bool) -> [Int] -> Maybe Int)
-    , fun "map" (map :: ([Int] -> Int) -> [[Int]] -> [Int])
-    , fun "inits" (inits :: [Int] -> [[Int]])
-    , fun "tail" (tail :: [[Int]] -> [[Int]])
-    ]
-
-  conjure "gps1" gps1p
-    [ unfun (0 :: Int)
-    , fun "+" ((+) :: Int -> Int -> Int)
-    , fun ">" ((>) :: Int -> Int -> Bool)
-    , fun "sum" (sum :: [Int] -> Int)
-    , fun "foldr" (foldr :: (Int -> Int -> Int) -> Int -> [Int] -> Int)
-    , fun "findIndex" (findIndex :: (Int -> Bool) -> [Int] -> Maybe Int)
-    , fun "map" (map :: ([Int] -> Int) -> [[Int]] -> [Int])
-    , fun "inits" (inits :: [Int] -> [[Int]])
-    , fun "tail" (tail :: [[Int]] -> [[Int]])
-    ]
-
-  conjure "gps1" gps1p2
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , fun "+" ((+) :: Int -> Int -> Int)
-    , fun "<" ((<) :: Int -> Int -> Bool)
-    , iif (undefined :: Int)
-    , fun "undefined" (undefined :: Int)
-    , maxSize 4
-    , maxEquationSize 4
-    ]
-
-
-gps2p :: Double -> Double -> Int -> Double
-gps2p 2 1 1  =  2 + 1
-gps2p 2 1 2  =  2 + 1 + 1 + 0.5
-gps2p 2 1 3  =  2 + 1 + 1 + 0.5 + 0.5 + 0.25
-gps2p 3 1 1  =  3 + 1
-gps2p 3 1 2  =  3 + 1 + 1/3
-
--- apex to apex
-gps2g :: Double -> Double -> Int -> Double
-gps2g h0 h1 0  =  h0 + h1
-gps2g h0 h1 n  =  h0 + h1 + gps2g h1 (h1 * (h1 / h0)) (n - 1)
--- size 17, out of reach performance-wise
-
-gps2c :: IO ()
-gps2c  =  do
-  conjure "gps2" gps2p
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , fun "*" ((*) :: Double -> Double -> Double)
-    , fun "/" ((/) :: Double -> Double -> Double)
-    , fun "+" ((+) :: Double -> Double -> Double)
-    , fun "-" ((-) :: Double -> Double -> Double)
-    , maxSize 6
-    ]
-
-
-gps3p :: String -> Int
-gps3p "X X X X X X X X X XXX"  =  300
-gps3p "11 11 11 11 11 11 11 11 11 11"  =  20
-
--- unreachable performance wise
--- I presume a correct solution would need around 30 symbols
-gps3c :: IO ()
-gps3c  =  conjure "gps3" gps3p []
-
-
-
--- GPS #4: https://www.codewars.com/kata/517abf86da9663f1d2000003
--- Here we're using the problem description as in the GPS2 paper
--- considering we're getting input as kebab-case.
--- Nevertheless, this one is out of reach performance-wise (and OOM-wise)
-
-gps4s :: (String -> String) -> [Property]
-gps4s g  =
-  [ property $ g "the-stealth-warrior" == "theStealthWarrior"
-  , property $ g "camel-case" == "camelCase"
-  , property $ g "Kebab-Case" == "KebabCase"
-  ]
-
-gps4g :: String -> String
-gps4g ""  =  ""
--- gps4g ('-':c:cs)  =  toUpper c : gps4g cs
--- gps4g ('_':c:cs)  =  toUpper c : gps4g cs
-gps4g (c:cs)  =  if c == '-'                                   --  5
-                 then if null cs                               --  8
-                      then ""                                  --  9
-                      else toUpper (head cs) : gps4g (tail cs) -- 16
-                 else c : gps4g cs                             -- 19
-
-gps4c :: IO ()
-gps4c  =  do
-  conjureFromSpec "gps4" gps4s
-    [ unfun '-'
-    , unfun ("" :: String)
-    , fun ":" ((:) :: Char -> String -> String)
-    , fun "==" ((==) :: Char -> Char -> Bool)
-    , fun "head" (head :: String -> Char)
-    , fun "tail" (tail :: String -> String)
-    , iif (undefined :: Char)
-    , iif (undefined :: String)
-    , fun "toUpper" (toUpper :: Char -> Char)
-    , maxSize 6
-    ]
-
-
--- GPS #5: Coin Sums
--- https://projecteuler.net/problem=31
---
--- The problem description is inconsistent with the one given in the paper.
---
--- Paper: change-making problem in USD
--- Euler: How many different ways can £2 be made using any number of coins?
---
--- I'm considering the Paper to be canonical, as the one in Project Euler can be solved by a constant function:
---
--- solution :: Int
--- solution  =  6378216738  -- <-- arbitrary example here, I didn't run the numbers
-gps5p :: Int -> [Int]
-gps5p 100  =  [4, 0, 0, 0]
-gps5p  50  =  [2, 0, 0, 0]
-gps5p  25  =  [1, 0, 0, 0]
-gps5p  30  =  [1, 0, 1, 0]
-gps5p  20  =  [0, 2, 0, 0]
-gps5p   3  =  [0, 0, 0, 3]
-
-gps5s :: ([Int] -> Int -> [Int]) -> [Property]
-gps5s t  =
-  [ property $ t [25, 10, 5, 1] 100 == [4, 0, 0, 0]
-  , property $ t [25, 10, 5, 1]  50 == [2, 0, 0, 0]
-  , property $ t [25, 10, 5, 1]  25 == [1, 0, 0, 0]
-  , property $ t [25, 10, 5, 1]  30 == [1, 0, 1, 0]
-  , property $ t [25, 10, 5, 1]  20 == [0, 2, 0, 0]
-  , property $ t [25, 10, 5, 1]   3 == [0, 0, 0, 3]
-  ]
-
-coins :: [Int]
-coins  =  [25, 10, 5, 1]
-
-gps5g :: Int -> [Int]
-gps5g  =  tell coins
-
-tell :: [Int] -> Int -> [Int]
-tell []     a  =  []
-tell (n:ns) a  =  a `div` n : tell ns (a `mod` n)
-
-gps5c :: IO ()
-gps5c  =  do
-  -- cannot conjure directly due to needing to introduce a local definition
-  conjure "gps5" gps5p
-    [
-    ]
-
-  conjureFromSpec "tell" gps5s
-    [ unfun ([] :: [Int])
-    , fun ":" ((:) :: Int -> [Int] -> [Int])
-    , fun "`div`" (div :: Int -> Int -> Int)
-    , fun "`mod`" (mod :: Int -> Int -> Int)
-    ]
-
-  conjure "gps5" gps5p
-    [ unfun coins
-    , fun "tell" tell
-    ]
-
-  conjure "gps5" gps5p
-    [ unfun (1 :: Int)
-    , unfun (5 :: Int)
-    , unfun (10 :: Int)
-    , unfun (25 :: Int)
-    , unfun ([] :: [Int])
-    , fun ":" ((:) :: Int -> [Int] -> [Int])
-    , fun "tell" tell
-    , target 50400
-    ]
-
-
--- GPS2#6: Cut Vector
-gps6g :: [Int] -> Int
-gps6g xs  =  snd
-          $  minimum
-          [  (abs (sum xs0 - sum xs1), i)
-          |  i <- [0 .. length xs]
-          ,  let (xs0, xs1) = splitAt i xs
-          ]
-
--- not Conjurable due to needing local definition
--- I conjecture it _perhaps-maybe_ this could be done in 3 steps,
--- but I'll leave this as-is for now.
-gps6c :: IO ()
-gps6c  =
-  conjure "gps6" gps6g []
-
-
--- GPS2#7: Dice Game
--- https://projecteuler.net/problem=31
--- https://github.com/thelmuth/Clojush/blob/psb2-v1.0/src/clojush/problems/psb2/dice_game.clj
--- again, paper and problem are inconsistent, going with paper
-gps7p :: Integer -> Integer -> Rational
-gps7p 4 6  =  1 % 4
-gps7p 6 4  =  7 % 12
-gps7p 2 4  =  1 % 8
-gps7p 4 2  =  5 % 8
-gps7p 2 6  =  1 % 12
-gps7p 6 2  =  3 % 4
-
-gps7g :: Integer -> Integer -> Rational
-gps7g peter colin  =  sum (map (min colin) [0 .. (peter-1)]) % (colin*peter)
-
--- out of reach performance-wise
-gps7c :: IO ()
-gps7c  =  do
-  conjure "gps7" gps7p $ take 0
-    [ unfun (0 :: Integer)
-    , unfun (1 :: Integer)
-    , fun "%" ((%) :: Integer -> Integer -> Rational)
-    , fun "+" ((+) :: Integer -> Integer -> Integer)
-    , fun "-" ((-) :: Integer -> Integer -> Integer)
-    , fun "*" ((*) :: Integer -> Integer -> Integer)
-    , fun "min" (min :: Integer -> Integer -> Integer)
-    , fun ".." (enumFromTo :: Integer -> Integer -> [Integer])
-    , fun "map" (map :: (Integer -> Integer) -> [Integer] -> [Integer])
-    , fun "sum" (sum :: [Integer] -> Integer)
-    , maxSize 6
-    ]
-
-
-gps8p :: Int -> [Int] -> (Int,Int)
-gps8p 2 [1,1,2]  =  (1,1)
-gps8p 3 [1,1,2]  =  (1,2)
-gps8p 2 [0,1,0,2]  =  (0,2)
-
-gps8g :: Int -> [Int] -> (Int,Int)
-gps8g x xs  =  head [(y,z) | y <- xs, z <- xs, y + z == x]
--- this one could be generated but is a bit of a stretch...
--- it is unintuitive to provide the given symbols
--- gps8g :: Int -> [Int] -> (Int,Int)
--- gps8g x xs  =  head $ filter ((x ==) . uncurry (+)) $ liftA2 (,) xs xs
-
-gps8c :: IO ()
-gps8c  =  conjure "gps8" gps8p []
-
-
--- GPSB#9: Fizz Buzz (CW)
-gps9p :: Int -> String
-gps9p 3  =  "Fizz"
-gps9p 4  =  "4"
-gps9p 5  =  "Buzz"
-gps9p 6  =  "Fizz"
-gps9p 10  =  "Buzz"
-gps9p 15  =  "FizzBuzz"
-gps9p 17  =  "17"
-
-gps9g :: Int -> String
-gps9g x
-  | x `div` 3 == 0  =  "Fizz" -- 7
-  | x `div` 5 == 0  =  "Buzz" -- 14
-  | x `div` 3 == 0 && x `div` 5 == 0  =  "FizzBuzz" -- 27
-  | otherwise       =  show x -- 29
-
--- probably unreachable performance-wise
-gps9c :: IO ()
-gps9c  =  conjure "gps9" gps9p []
-
-
-gps10p :: [Int] -> Int
-gps10p [0]  =  -2
-gps10p [3]  =  -1
-gps10p [6]  =  0
-gps10p [9]  =  1
-gps10p [0,3]  =  -3
-gps10p [3,0]  =  -3
-gps10p [3,2,1]  =  -5
-gps10p [1,2,3]  =  -5
-gps10p [10,20,30]  =  13
-
--- does not do rounding
-gps10g :: [Int] -> Int
-gps10g []  =  0
-gps10g (x:xs)  =  (x `div` 3 - 2) + gps10g xs
-
--- unreachable due to lambda
-gps10c :: IO ()
-gps10c  =  conjure "gps10" gps10p
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
-  , unfun (2 :: Int)
-  , unfun (3 :: Int)
-  , fun "`div`" (div :: Int -> Int -> Int)
-  , fun "+" ((+) :: Int -> Int -> Int)
-  , fun "-" ((-) :: Int -> Int -> Int)
-  , target 50400
-  ]
-
-
-gps11p :: Int -> Int -> Int
-gps11p  =  gcd'
-  where
-  gcd' :: Int -> Int -> Int
-  gcd' 1 1  =  1
-  gcd' 1 2  =  1
-  gcd' 2 1  =  1
-  gcd' 2 2  =  2
-  gcd' 2 6  =  2
-  gcd' 6 2  =  2
-  gcd' 3 6  =  3
-  gcd' 6 3  =  3
-  gcd' 6 9  =  3
-  gcd' 9 6  =  3
-  gcd' 12 18  =  6
-
-gps11c :: IO ()
-gps11c  =  conjure "gcd a b" gps11p
-  [ unfun (0::Int)
-  , fun "`mod`" (mod :: Int -> Int -> Int)
-  ]
-  -- generated function:
-  -- gcd x 0  =  x
-  -- gcd x y  =  gcd y (x `mod` y)
-
-
-gps12p :: String -> String -> [Int]
-gps12p "a"   "a"   =  [0]
-gps12p "aa"  "a"   =  [0,1]
-gps12p "aa"  "aa"  =  [0]
-gps12p "a a" "a"   =  [0,2]
-gps12p "b"   "a"   =  []
-
-gps12g :: String -> String -> [Int]
-gps12g s s'  =  findIndices (s' `isPrefixOf`) (tails s)
-
-gps12c :: IO ()
-gps12c  =  conjure "gps12" gps12p
-  [ fun "findIndices" (findIndices :: (String -> Bool) -> [String] -> [Int])
-  , fun "`isPrefixOf`" (isPrefixOf :: String -> String -> Bool)
-  , fun "tails" (tails :: String -> [String])
-  ]
-
-
-gps13p :: [Int] -> [Int]
-gps13p [0,1]  =  [1]
-gps13p [1,0]  =  [1,0]
-gps13p [2,0,1]  =  [2,1]
-gps13p [1,0,1]  =  [1]
-
-gps13g :: [Int] -> [Int]
-gps13g  =  leaders
-  where
-  leaders []  =  []
-  leaders (x:xs)  =  if all (x >) xs
-                     then x : leaders xs
-                     else leaders xs
-
-gps13c :: IO ()
-gps13c  =  conjure "gps13_leaders" gps13p
-  [ unfun ([] :: [Int])
-  , fun ":" ((:) :: Int -> [Int] -> [Int])
-  , fun ">" ((>) :: Int -> Int -> Bool)
-  , fun "all" (all :: (Int -> Bool) -> [Int] -> Bool)
-  , iif (undefined :: [Int])
-  ]
-
-
-gps14p :: [Int] -> Int
-gps14p  =  undefined
-
--- 30 symbols
-gps14g :: [Int] -> Int
-gps14g  =  luhn
-  where
-  luhn :: [Int] -> Int
-  luhn xs  =  sum (firsts xs ++ map double9 (seconds xs))
-    where
-    double9 :: Int -> Int
-    double9 x  =  if xx > 9
-                  then xx - 9
-                  else xx
-      where
-      xx  =  x * 2
-    seconds :: [Int] -> [Int]
-    seconds []  =  []
-    seconds (x:y:xs)  =  y : seconds xs
-    firsts :: [Int] -> [Int]
-    firsts []  =  []
-    firsts (x:y:xs)  =  x : seconds xs
-
--- cannot Conjure directly
-gps14c :: IO ()
-gps14c  =  conjure "gps14_luhn" gps14p
-  [
-  ]
-
-
-gps15p :: () -> ()
-gps15p  =  undefined
-
--- skipped
-gps15c :: IO ()
-gps15c  =  conjure "gps15_mastermind" gps15p []
-
-
-gps16p :: String -> String
-gps16p "a"      =  "a"
-gps16p "aaa"    =  "a"
-gps16p "aa"     =  "aa"
-gps16p "a a"    =  " "
-gps16p " a "    =  "a"
-gps16p "a a "   =  " a"
-gps16p " a a "  =  " "
-
-gps16g1 :: String -> String
-gps16g1 s  =  if odd len
-              then take 1 (drop (len `div` 2) s)
-              else take 2 (drop (len `div` 2 - 1) s)
-  where
-  len  =  length s
-
-gps16g2 :: String -> String
-gps16g2 ""  =  ""
-gps16g2 (c:cs)  =  if length cs <= 1
-                   then c : cs
-                   else gps16g2 (init cs)
-
-gps16c :: IO ()
-gps16c  =  conjure "gps16_middle" gps16p
-  [ unfun ""
-  , unfun (1 :: Int)
-  , fun "<=" ((<=) :: Int -> Int -> Bool)
-  , fun ":" ((:) :: Char -> String -> String)
-  , fun "length" (length :: String -> Int)
-  , fun "init" (init :: String -> String)
-  , iif (undefined :: String)
-  ]
-
-
-gps17p :: [Int] -> Int
-gps17p [0,1,0]  =  0
-gps17p [1,1]  =  1
-gps17p [1,1,0]  =  1
-gps17p [0,1,1]  =  1
-gps17p [1,1,1]  =  2
-
-gps17g :: [Int] -> Int
-gps17g xs  =  pds xs
-  where
-  pds []  =  0
-  pds (x:xs)  =  if not (null xs) && x == head xs
-                 then x + pds xs
-                 else pds xs
--- surprise:
--- gps17_pds []  =  0
--- gps17_pds (x:xs)  =  (if not (null xs) && head xs == x then x else 0) + gps17_pds xs
-
-
--- can generate at size 15 in 18 seconds
--- setting limit of 5 for faster automated tests
--- BENCHMARK: increase maxSize from 5 to 18
-gps17c :: IO ()
-gps17c  =  conjure "gps17_pds" gps17p
-  [ unfun (0 :: Int)
-  , iif (undefined :: Int)
-  , fun "not" not
-  , fun "null" (null :: [Int] -> Bool)
-  , fun "==" ((==) :: Int -> Int -> Bool)
-  , fun "head" (head :: [Int] -> Int)
-  , fun "+" ((+) :: Int -> Int -> Int)
-  , fun "&&" (&&)
-  , maxSize 5
-  ]
-
-
-gps18p :: [Double] -> [Double] -> Double
-gps18p [1.0] [0.5]  =  0.5
-gps18p [2.0] [0.5]  =  1.0
-gps18p [1.0,1.0] [0.5,0.0]  =  1.5
-gps18p [1.0,1.0] [0.0,0.5]  =  1.5
-
-gps18g :: [Double] -> [Double] -> Double
-gps18g prices discounts  =  foldr (+) 0 (zipWith (*) prices (map (1-) discounts))
-
--- this was OOM'd
-gps18c :: IO ()
-gps18c  =  conjure "gps18_price" gps18p
-  [ unfun (0 :: Double)
-  , unfun (1 :: Double)
-  , fun "+" ((+) :: Double -> Double -> Double)
-  , fun "*" ((*) :: Double -> Double -> Double)
-  , fun "-" ((-) :: Double -> Double -> Double)
---  , fun "foldr" (foldr :: (Double -> Double -> Double) -> Double -> [Double] -> Double)
---   , fun "zipWith" (zipWith :: (Double -> Double -> Double) -> [Double] -> [Double] -> [Double])
---  , fun "map" (map :: (Double -> Double) -> [Double] -> [Double])
-  , maxSize 6
-  ]
-
-
-gps19p :: Int -> Double -> Double -> Double -> Double
-gps19p 0 0 1.0 1.0  =  0
-gps19p 1 0 1.0 1.0  =  0
-gps19p 2 0 1.0 1.0  =  0
-gps19p 1 0 1.0 2.0  =  1.0
-gps19p 2 0 1.0 2.0  =  2.0
-gps19p 1 0 0.5 1.0  =  0.5
-gps19p 2 0 0.5 1.0  =  1.0
-
-gps19g :: Int -> Double -> Double -> Double -> Double
-gps19g 0 total melt fall  =  total
-gps19g n total melt fall  =  gps19p (n-1) (max 0 (total-melt+fall)) melt fall
--- size 14, out of reach performance wise.
-
-gps19c :: IO ()
-gps19c  =  conjure "gps19_snowday" gps19p
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
-  , fun "max" (max :: Double -> Double -> Double)
-  , fun "+" ((+) :: Double -> Double -> Double)
-  , fun "-" ((-) :: Double -> Double -> Double)
-  , maxSize 6
-  ]
-
-
-gps20p :: String -> Bool
-gps20p  =  undefined
-
-gps20c :: IO ()
-gps20c  =  conjure "gps20" gps20p
-  [
-  ]
-
-
-gps21s :: (String -> String) -> [Property]
-gps21s s  =
-  [ property $ s "word" == "word"
-  , property $ s "words" == "sdrow"
-  , property $ s "word words" == "word sdrow"
-  , property $ s "words word" == "sdrow word"
-  ]
-
-spinSpec :: (String -> String) -> [Property]
-spinSpec spin  =
-  [ property $ spin "abc" == "abc"
-  , property $ spin "abcd" == "abcd"
-  , property $ spin "word" == "word"
-  , property $ spin "abcde" == "edcba"
-  , property $ spin "words" == "sdrow"
-  , property $ spin "hello" == "olleh"
-  , property $ spin "world" == "dlrow"
-  ]
-
-spin :: String -> String
-spin w  =  if length w >= 5
-           then reverse w
-           else w
-
-gps21g :: String -> String
-gps21g s  =  unwords (map spin (words s))
-
-gps21c :: IO ()
-gps21c  =  do
-  conjureFromSpec "spin" spinSpec
-    [ fun "length"  (length :: String -> Int)
-    , fun "reverse" (reverse :: String -> String)
-    , iif (undefined :: String)
-    , fun ">="      ((>=) :: Int -> Int -> Bool)
-    , unfun (5 :: Int)
-    ]
-
-  conjureFromSpec "gps21_spinwords" gps21s
-    [ fun "words"   words
-    , fun "unwords" unwords
-    , fun "spin"    (spin :: String -> String)
-    , fun "map"     (map :: (String -> String) -> [String] -> [String])
-    , fun "length"  (length :: String -> Int)
-    , fun "reverse" (reverse :: String -> String)
-    , iif (undefined :: String)
-    , fun ">="      ((>=) :: Int -> Int -> Bool)
-    , unfun (5 :: Int)
-    ]
-
-
-digits :: Int -> [Int]
-digits 0  =  []
-digits n  =  n `mod` 10 : digits (n `div` 10)
-
-digits' :: Int -> [Int]
-digits' 1  =  [1]
-digits' 12  =  [2,1]
-digits' 21  =  [1,2]
-digits' 123  =  [3,2,1]
-digits' 321  =  [1,2,3]
-
-gps22p :: Int -> String
-gps22p  =  undefined
-
-gps22c :: IO ()
-gps22c  =  do
-  -- cannot conjure at size 13, maybe beyond?
-  conjure "digits" digits'
-    [ unfun ([] :: [Int])
-    , fun ":" ((:) :: Int -> [Int] -> [Int])
-    , fun "`div`" (div :: Int -> Int -> Int)
-    , fun "`mod`" (mod :: Int -> Int -> Int)
-    , fun "div10" ((`div` 10) :: Int -> Int)
-    , unfun (10 :: Int)
-    , target 10080
-    ]
-
-  conjure "gps22" gps22p
-    [
-    ]
-
-
-gps23s :: (String -> String -> String -> String) -> [Property]
-gps23s s  =
-  [ property $ s "abcd" "abcd" "abcd" == "abcd"
-  , property $ s "abcd" "dcba" "abcd" == "dcba"
-  , property $ s "abcd" "1234" "abcd" == "1234"
-  , property $ s "abcd" "1234" "bacd" == "2134"
-  ]
-
-gps23g :: String -> String -> String -> String
--- gps23g f t s  =  map (\c -> fromJust $ c `lookup` zipWith (,) f t) s
-gps23g f t s  =  map (fromJust . (`lookup` zipWith (,) f t)) s
-
-gps23c :: IO ()
-gps23c  =  do
-  -- cannot conjure, needs lambda
-  conjureFromSpec "gps23" gps23s
-    [
-    ]
-
-
-data Twitter  =  Tweet Int
-              |  TooMany
-              |  Empty
-              deriving (Eq, Show)
-
-deriveExpress  ''Twitter
-deriveListable ''Twitter
-deriveName     ''Twitter
-
-instance Conjurable Twitter where
-  conjureExpress   =  reifyExpress
-  conjureEquality  =  reifyEquality
-  conjureTiers     =  reifyTiers
-
-gps24g_twitter :: String -> Twitter
-gps24g_twitter ""  =  Empty
-gps24g_twitter s  =  if length s > 140
-                     then TooMany
-                     else Tweet (length s)
-
-gps24s_twitter :: (String -> Twitter) -> [Property]
-gps24s_twitter twitter  =
-  [ property $ twitter "" == Empty
-  , property $ twitter "abcd" == Tweet 4
-  , property $ twitter "0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij" == Tweet 140
-  , property $ twitter "0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghijX" == TooMany
-  ]
-
-gps24c :: IO ()
-gps24c  =  do
-  conjureFromSpec "gps24" gps24s_twitter
-    [ unfun Empty
-    , unfun TooMany
-    , fun "Tweet" Tweet
-    , iif (undefined :: Twitter)
-    , unfun ""
-    , fun ":" ((:) :: Char -> String -> String)
-    , fun "length" (length :: String -> Int)
-    , unfun (140 :: Int)
-    , fun ">" ((>) :: Int -> Int -> Bool)
-    ]
-
-
-gps25p :: [Double] -> [Double] -> Double
-gps25p [0] [1]  =  1
-gps25p [1] [0]  =  1
-gps25p [-1] [1]  =  2
-gps25p [0,1] [1,0]  =  sqrt 2
-gps25p [1,0] [0,1]  =  sqrt 2
-gps25p [0,0,1] [1,0,0]  =  sqrt 2
-gps25p [0,1,2] [1,2,3]  =  sqrt 3
-
-gps25g :: [Double] -> [Double] -> Double
-gps25g v1 v2  =  sqrt (foldr (+) 0 (map (^2) (zipWith (-) v1 v2)))
-
--- out of reach performance-wise
-gps25c :: IO ()
-gps25c  =  conjure "gps25" gps25p
-  [ unfun (0 :: Double)
-  , unfun (2 :: Double)
-  , fun "+" ((+) :: Double -> Double -> Double)
-  , fun "-" ((-) :: Double -> Double -> Double)
-  , fun "**" ((**) :: Double -> Double -> Double)
-  , fun "zipWith" (zipWith :: (Double -> Double -> Double) -> [Double] -> [Double] -> [Double])
-  , fun "map" (map :: (Double -> Double) -> [Double] -> [Double])
-  , fun "sqrt" (sqrt :: Double -> Double)
-  , maxSize 6
-  ]
-
-
-main :: IO ()
-main  =  do
-  as <- getArgs
-  case as of
-    [] -> sequence_ gpss
-    (n:_) -> gpss !! (read n - 1)
-
-
-gpss :: [IO ()]
-gpss  =  [ gps1c
-         , gps2c
-         , gps3c
-         , gps4c
-         , gps5c
-         , gps6c
-         , gps7c
-         , gps8c
-         , gps9c
-         , gps10c
-         , gps11c
-         , gps12c
-         , gps13c
-         , gps14c
-         , gps15c
-         , gps16c
-         , gps17c
-         , gps18c
-         , gps19c
-         , gps20c
-         , gps21c
-         , gps22c
-         , gps23c
-         , gps24c
-         , gps25c
-         ]
diff --git a/bench/gps2.txt b/bench/gps2.txt
deleted file mode 100644
--- a/bench/gps2.txt
+++ /dev/null
@@ -1,367 +0,0 @@
-gps1 :: [Int] -> Maybe Int
--- testing 4 combinations of argument values
--- pruning with 11/21 rules
--- 0 candidates of size 1
--- 0 candidates of size 2
--- 0 candidates of size 3
--- 1 candidates of size 4
--- 0 candidates of size 5
--- 0 candidates of size 6
--- 1 candidates of size 7
--- 0 candidates of size 8
--- 1 candidates of size 9
--- 2 candidates of size 10
--- tested 5 candidates
-gps1 xs  =  findIndex (0 >) (map (foldr (+) 0) (tail (inits xs)))
-
-gps1 :: [Int] -> Maybe Int
--- testing 4 combinations of argument values
--- pruning with 11/21 rules
--- 0 candidates of size 1
--- 0 candidates of size 2
--- 0 candidates of size 3
--- 1 candidates of size 4
--- 1 candidates of size 5
--- 0 candidates of size 6
--- 1 candidates of size 7
--- 4 candidates of size 8
--- tested 6 candidates
-gps1 xs  =  findIndex (0 >) (map sum (tail (inits xs)))
-
-gps1 :: Int -> [Int] -> Int
--- testing 6 combinations of argument values
--- pruning with 8/9 rules
--- 4 candidates of size 1
--- 0 candidates of size 2
--- 11 candidates of size 3
--- 29 candidates of size 4
--- tested 44 candidates
-gps1  =  undefined  -- search exhausted
-
-gps2 :: Double -> Double -> Int -> Double
--- testing 5 combinations of argument values
--- pruning with 2/6 rules
--- 2 candidates of size 1
--- 2 candidates of size 2
--- 16 candidates of size 3
--- 64 candidates of size 4
--- 256 candidates of size 5
--- 1252 candidates of size 6
--- tested 1592 candidates
-gps2  =  undefined  -- search exhausted
-
-gps3 :: [Char] -> Int
-gps3  =  error "could not reify specification, suggestion: conjureFromSpec"
-
-gps4 :: [Char] -> [Char]
--- pruning with 13/21 rules
--- 2 candidates of size 1
--- 3 candidates of size 2
--- 8 candidates of size 3
--- 20 candidates of size 4
--- 51 candidates of size 5
--- 119 candidates of size 6
--- tested 203 candidates
-gps4  =  undefined  -- search exhausted
-
-gps5 :: Int -> [Int]
--- testing 6 combinations of argument values
--- pruning with 0/0 rules
--- 0 candidates of size 1
--- tested 0 candidates
-gps5  =  undefined  -- search exhausted
-
-tell :: [Int] -> Int -> [Int]
--- pruning with 0/0 rules
--- 2 candidates of size 1
--- 1 candidates of size 2
--- 2 candidates of size 3
--- 6 candidates of size 4
--- 6 candidates of size 5
--- 39 candidates of size 6
--- 26 candidates of size 7
--- 328 candidates of size 8
--- 134 candidates of size 9
--- 3229 candidates of size 10
--- tested 783 candidates
-tell [] x  =  []
-tell (x:xs) y  =  y `div` x:tell xs (y `mod` x)
-
-gps5 :: Int -> [Int]
--- testing 6 combinations of argument values
--- pruning with 0/0 rules
--- 1 candidates of size 1
--- 0 candidates of size 2
--- 1 candidates of size 3
--- tested 2 candidates
-gps5  =  tell [25,10,5,1]
-
-gps5 :: Int -> [Int]
--- testing 6 combinations of argument values
--- pruning with 12/12 rules
--- 1 candidates of size 1
--- 0 candidates of size 2
--- 5 candidates of size 3
--- 9 candidates of size 4
--- 45 candidates of size 5
--- 82 candidates of size 6
--- 428 candidates of size 7
--- 882 candidates of size 8
--- 4350 candidates of size 9
--- 9232 candidates of size 10
--- 43847 candidates of size 11
--- tested 32290 candidates
-gps5  =  tell [25,10,5,1]
-
-gps6 :: [Int] -> Int
--- testing 360 combinations of argument values
--- pruning with 0/0 rules
--- 0 candidates of size 1
--- 0 candidates of size 2
--- tested 0 candidates
-gps6  =  undefined  -- search exhausted
-
-gps7 :: Integer -> Integer -> Ratio Integer
--- testing 6 combinations of argument values
--- pruning with 0/0 rules
--- 0 candidates of size 1
--- tested 0 candidates
-gps7  =  undefined  -- search exhausted
-
-gps8 :: Int -> [Int] -> (Int,Int)
--- testing 3 combinations of argument values
--- pruning with 0/0 rules
--- 0 candidates of size 1
--- 0 candidates of size 2
--- tested 0 candidates
-gps8  =  undefined  -- search exhausted
-
-gps9 :: Int -> [Char]
--- testing 7 combinations of argument values
--- pruning with 0/0 rules
--- 0 candidates of size 1
--- tested 0 candidates
-gps9  =  undefined  -- search exhausted
-
-gps10 :: [Int] -> Int
--- testing 7 combinations of argument values
--- pruning with 67/100 rules
--- 4 candidates of size 1
--- 0 candidates of size 2
--- 0 candidates of size 3
--- 0 candidates of size 4
--- 80 candidates of size 5
--- 8 candidates of size 6
--- 1428 candidates of size 7
--- 432 candidates of size 8
--- 30712 candidates of size 9
--- tested 7064 candidates
-gps10 []  =  0
-gps10 (x:xs)  =  (x `div` 3 - 2) + gps10 xs
-
-gcd :: Int -> Int -> Int
--- testing 11 combinations of argument values
--- pruning with 0/0 rules
--- 3 candidates of size 1
--- 6 candidates of size 2
--- 11 candidates of size 3
--- 50 candidates of size 4
--- 98 candidates of size 5
--- 330 candidates of size 6
--- tested 172 candidates
-gcd x 0  =  x
-gcd x y  =  gcd y (x `mod` y)
-
-gps12 :: [Char] -> [Char] -> [Int]
--- testing 5 combinations of argument values
--- pruning with 1/2 rules
--- 0 candidates of size 1
--- 0 candidates of size 2
--- 0 candidates of size 3
--- 0 candidates of size 4
--- 4 candidates of size 5
--- tested 3 candidates
-gps12 cs ds  =  findIndices (ds `isPrefixOf`) (tails cs)
-
-gps13_leaders :: [Int] -> [Int]
--- testing 4 combinations of argument values
--- pruning with 5/5 rules
--- 2 candidates of size 1
--- 0 candidates of size 2
--- 0 candidates of size 3
--- 0 candidates of size 4
--- 1 candidates of size 5
--- 0 candidates of size 6
--- 1 candidates of size 7
--- 0 candidates of size 8
--- 7 candidates of size 9
--- 4 candidates of size 10
--- 33 candidates of size 11
--- 18 candidates of size 12
--- tested 53 candidates
-gps13_leaders []  =  []
-gps13_leaders (x:xs)  =  if all (x >) xs
-                         then x:gps13_leaders xs
-                         else gps13_leaders xs
-
-gps14_luhn :: [Int] -> Int
-gps14_luhn  =  error "could not reify specification, suggestion: conjureFromSpec"
-
-gps15_mastermind :: () -> ()
-gps15_mastermind  =  error "could not reify specification, suggestion: conjureFromSpec"
-
-gps16_middle :: [Char] -> [Char]
--- testing 7 combinations of argument values
--- pruning with 10/11 rules
--- 2 candidates of size 1
--- 2 candidates of size 2
--- 2 candidates of size 3
--- 3 candidates of size 4
--- 6 candidates of size 5
--- 11 candidates of size 6
--- 23 candidates of size 7
--- 62 candidates of size 8
--- 175 candidates of size 9
--- 489 candidates of size 10
--- 1346 candidates of size 11
--- 3709 candidates of size 12
--- tested 2390 candidates
-gps16_middle ""  =  ""
-gps16_middle (c:cs)  =  if length cs <= 1
-                        then c:cs
-                        else gps16_middle (init cs)
-
-gps17_pds :: [Int] -> Int
--- testing 5 combinations of argument values
--- pruning with 29/40 rules
--- 1 candidates of size 1
--- 1 candidates of size 2
--- 0 candidates of size 3
--- 0 candidates of size 4
--- 2 candidates of size 5
--- tested 4 candidates
-gps17_pds  =  undefined  -- search exhausted
-
-gps18_price :: [Double] -> [Double] -> Double
--- testing 4 combinations of argument values
--- pruning with 26/35 rules
--- 2 candidates of size 1
--- 0 candidates of size 2
--- 2 candidates of size 3
--- 0 candidates of size 4
--- 33 candidates of size 5
--- 176 candidates of size 6
--- tested 213 candidates
-gps18_price  =  undefined  -- search exhausted
-
-gps19_snowday :: Int -> Double -> Double -> Double -> Double
--- testing 7 combinations of argument values
--- pruning with 6/19 rules
--- 3 candidates of size 1
--- 2 candidates of size 2
--- 21 candidates of size 3
--- 39 candidates of size 4
--- 312 candidates of size 5
--- 659 candidates of size 6
--- tested 1036 candidates
-gps19_snowday  =  undefined  -- search exhausted
-
-gps20 :: [Char] -> Bool
-gps20  =  error "could not reify specification, suggestion: conjureFromSpec"
-
-spin :: [Char] -> [Char]
--- pruning with 6/6 rules
--- reasoning produced 1 incorrect properties, please re-run with more tests for faster results
--- 1 candidates of size 1
--- 1 candidates of size 2
--- 0 candidates of size 3
--- 0 candidates of size 4
--- 0 candidates of size 5
--- 0 candidates of size 6
--- 0 candidates of size 7
--- 4 candidates of size 8
--- tested 3 candidates
-spin cs  =  if length cs >= 5
-            then reverse cs
-            else cs
-
-gps21_spinwords :: [Char] -> [Char]
--- pruning with 16/16 rules
--- reasoning produced 2 incorrect properties, please re-run with more tests for faster results
--- 1 candidates of size 1
--- 2 candidates of size 2
--- 2 candidates of size 3
--- 3 candidates of size 4
--- 5 candidates of size 5
--- tested 12 candidates
-gps21_spinwords cs  =  unwords (map spin (words cs))
-
-digits :: Int -> [Int]
--- testing 5 combinations of argument values
--- pruning with 7/7 rules
--- 1 candidates of size 1
--- 0 candidates of size 2
--- 2 candidates of size 3
--- 3 candidates of size 4
--- 11 candidates of size 5
--- 13 candidates of size 6
--- 91 candidates of size 7
--- 104 candidates of size 8
--- 850 candidates of size 9
--- 923 candidates of size 10
--- 8902 candidates of size 11
--- tested 10900 candidates
-digits  =  undefined  -- search exhausted
-
-gps22 :: Int -> [Char]
-gps22  =  error "could not reify specification, suggestion: conjureFromSpec"
-
-gps23 :: [Char] -> [Char] -> [Char] -> [Char]
--- pruning with 0/0 rules
--- 3 candidates of size 1
--- 12 candidates of size 2
--- 33 candidates of size 3
--- 36 candidates of size 4
--- 127 candidates of size 5
--- 507 candidates of size 6
--- 839 candidates of size 7
--- 784 candidates of size 8
--- 600 candidates of size 9
--- 2722 candidates of size 10
--- 5292 candidates of size 11
--- tested 10955 candidates
-gps23  =  undefined  -- search exhausted
-
-gps24 :: [Char] -> Twitter
--- pruning with 4/8 rules
--- reasoning produced 4 incorrect properties, please re-run with more tests for faster results
--- 2 candidates of size 1
--- 3 candidates of size 2
--- 6 candidates of size 3
--- 6 candidates of size 4
--- 3 candidates of size 5
--- 5 candidates of size 6
--- 10 candidates of size 7
--- 48 candidates of size 8
--- 134 candidates of size 9
--- 216 candidates of size 10
--- 308 candidates of size 11
--- 466 candidates of size 12
--- tested 881 candidates
-gps24 ""  =  Empty
-gps24 (c:cs)  =  if 140 > length cs
-                 then Tweet (length (c:cs))
-                 else TooMany
-
-gps25 :: [Double] -> [Double] -> Double
--- testing 6 combinations of argument values
--- pruning with 31/59 rules
--- 2 candidates of size 1
--- 1 candidates of size 2
--- 5 candidates of size 3
--- 10 candidates of size 4
--- 76 candidates of size 5
--- 438 candidates of size 6
--- tested 532 candidates
-gps25  =  undefined  -- search exhausted
-
diff --git a/bench/i12.hs b/bench/i12.hs
new file mode 100644
--- /dev/null
+++ b/bench/i12.hs
@@ -0,0 +1,71 @@
+-- 12 background ingredients
+--
+-- Copyright (C) 2021-2025 Rudy Matela
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+import Conjure
+import System.Environment
+
+factorial :: Int -> Int
+factorial 0  =  1
+factorial 1  =  1
+factorial 2  =  2
+factorial 3  =  6
+factorial 4  =  24
+factorial 5  =  120
+
+count' :: Int -> [Int] -> Int
+count' 0 [0]  =  1
+count' 0 [1]  =  0
+count' 1 [0]  =  0
+count' 1 [1]  =  1
+count' 0 [0,0]  =  2
+count' 0 [0,1]  =  1
+count' 0 [1,2]  =  0
+count' 1 [0,0]  =  0
+count' 1 [0,1]  =  1
+count' 1 [1,2]  =  1
+count' 0 [0,0,0]  =  3
+count' 0 [0,0,1]  =  2
+count' 0 [1,0,0]  =  2
+
+main :: IO ()
+main  =  do
+  putStrLn $ "running with " ++ show (length ingredients) ++ " ingredients"
+  as <- getArgs
+  case as of
+    ["factorial"]     -> conjure "factorial n" factorial   ingredients
+    ["factorial","t"] -> conjure "factorial n" factorial $ ingredients ++ [maxSize 1]
+    ["sum"]           -> conjure "sum"     (sum     :: [Int] -> Int)   ingredients
+    ["sum","t"]       -> conjure "sum"     (sum     :: [Int] -> Int) $ ingredients ++ [maxSize 1]
+    ["product"]       -> conjure "product" (product :: [Int] -> Int)   ingredients
+    ["product","t"]   -> conjure "product" (product :: [Int] -> Int) $ ingredients ++ [maxSize 1]
+    ["length"]        -> conjure "length"  (length  :: [Int] -> Int)   ingredients
+    ["length","t"]    -> conjure "length"  (length  :: [Int] -> Int) $ ingredients ++ [maxSize 1]
+    ["count"]         -> conjure "count"   count' $ ingredients ++ primsCount
+    ["count","t"]     -> conjure "count"   count' $ ingredients ++ primsCount ++ [maxSize 1]
+    _                 -> conjure "factorial n" factorial ingredients
+
+ingredients :: [Ingredient]
+ingredients  =
+  [ con (0::Int)
+  , con (1::Int)
+  , fun "+" ((+) :: Int -> Int -> Int)
+  , fun "*" ((*) :: Int -> Int -> Int)
+  , fun "dec" (subtract 1 :: Int -> Int)
+
+  , fun "==" ((==) :: Int -> Int -> Bool)
+
+  , con ([] :: [Int])
+  , fun ":" ((:) :: Int -> [Int] -> [Int])
+  , fun "head" (head :: [Int] -> Int)
+  , fun "tail" (tail :: [Int] -> [Int])
+  , fun "null" (null :: [Int] -> Bool)
+  , fun "foldr" (foldr :: (Int -> Int -> Int) -> Int -> [Int] -> Int)
+  , fun ".." (enumFromTo :: Int -> Int -> [Int])
+  ]
+
+primsCount :: [Ingredient]
+primsCount  =
+  [ fun "length" (length :: [Int] -> Int)
+  , fun "filter" (filter :: (Int -> Bool) -> [Int] -> [Int])
+  ]
diff --git a/bench/i12.txt b/bench/i12.txt
new file mode 100644
--- /dev/null
+++ b/bench/i12.txt
@@ -0,0 +1,13 @@
+running with 13 ingredients
+factorial :: Int -> Int
+-- testing 6 combinations of argument values
+-- pruning with 67/101 rules
+-- 3 candidates of size 1
+-- 1 candidates of size 2
+-- 4 candidates of size 3
+-- 8 candidates of size 4
+-- 28 candidates of size 5
+-- 109 candidates of size 6
+-- tested 146 candidates
+factorial x  =  foldr (*) 1 [1..x]
+
diff --git a/bench/i30.hs b/bench/i30.hs
new file mode 100644
--- /dev/null
+++ b/bench/i30.hs
@@ -0,0 +1,87 @@
+-- 30 background ingredients, does Conjure scale?
+--
+-- Copyright (C) 2021-2025 Rudy Matela
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+import Conjure
+import System.Environment
+
+factorial :: Int -> Int
+factorial 0  =  1
+factorial 1  =  1
+factorial 2  =  2
+factorial 3  =  6
+factorial 4  =  24
+factorial 5  =  120
+
+count' :: Int -> [Int] -> Int
+count' 0 [0]  =  1
+count' 0 [1]  =  0
+count' 1 [0]  =  0
+count' 1 [1]  =  1
+count' 0 [0,0]  =  2
+count' 0 [0,1]  =  1
+count' 0 [1,2]  =  0
+count' 1 [0,0]  =  0
+count' 1 [0,1]  =  1
+count' 1 [1,2]  =  1
+count' 0 [0,0,0]  =  3
+count' 0 [0,0,1]  =  2
+count' 0 [1,0,0]  =  2
+
+main :: IO ()
+main  =  do
+  putStrLn $ "running with " ++ show (length ingredients) ++ " ingredients"
+  as <- getArgs
+  case as of
+    ["factorial"]     -> conjure "factorial n" factorial   ingredients
+    ["factorial","t"] -> conjure "factorial n" factorial $ ingredients ++ [maxSize 1]
+    ["sum"]           -> conjure "sum"     (sum     :: [Int] -> Int)   ingredients
+    ["sum","t"]       -> conjure "sum"     (sum     :: [Int] -> Int) $ ingredients ++ [maxSize 1]
+    ["product"]       -> conjure "product" (product :: [Int] -> Int)   ingredients
+    ["product","t"]   -> conjure "product" (product :: [Int] -> Int) $ ingredients ++ [maxSize 1]
+    ["length"]        -> conjure "length"  (length  :: [Int] -> Int)   ingredients
+    ["length","t"]    -> conjure "length"  (length  :: [Int] -> Int) $ ingredients ++ [maxSize 1]
+    ["count"]         -> conjure "count"   count' $ ingredients ++ primsLength
+    ["count","t"]     -> conjure "count"   count' $ ingredients ++ primsLength ++ [maxSize 1]
+    _                 -> putStrLn "usage: p30 <factorial|sum|product|length|count> [t]"
+
+ingredients :: [Ingredient]
+ingredients  =
+  [ con False
+  , con True
+  , fun "&&" (&&)
+  , fun "||" (||)
+  , fun "not" not
+
+  , con (0::Int)
+  , con (1::Int)
+  , fun "+" ((+) :: Int -> Int -> Int)
+  , fun "*" ((*) :: Int -> Int -> Int)
+  , fun "dec" (subtract 1 :: Int -> Int)
+  , fun "-" ((-) :: Int -> Int -> Int)
+
+  , fun "==" ((==) :: Int -> Int -> Bool)
+  , fun "<=" ((<=) :: Int -> Int -> Bool)
+  , fun "<"  ((<) :: Int -> Int -> Bool)
+
+  , fun "const" (const :: Int -> Int -> Int)
+
+  , con ([] :: [Int])
+  , fun ":" ((:) :: Int -> [Int] -> [Int])
+  , fun "head" (head :: [Int] -> Int)
+  , fun "tail" (tail :: [Int] -> [Int])
+  , fun "null" (null :: [Int] -> Bool)
+  , fun "foldr" (foldr :: (Int -> Int -> Int) -> Int -> [Int] -> Int)
+
+  , fun "map" (map :: (Int -> Int) -> [Int] -> [Int])
+  , fun "filter" (filter :: (Int -> Bool) -> [Int] -> [Int])
+  , fun ".." (enumFromTo :: Int -> Int -> [Int])
+
+  , fun "++" ((++) :: [Int] -> [Int] -> [Int])
+  , fun "elem" (elem :: Int -> [Int] -> Bool)
+  ]
+
+primsLength :: [Ingredient]
+primsLength =
+  [ fun "length" (length :: [Int] -> Int)
+  ]
diff --git a/bench/i30.txt b/bench/i30.txt
new file mode 100644
--- /dev/null
+++ b/bench/i30.txt
@@ -0,0 +1,2 @@
+running with 26 ingredients
+usage: p30 <factorial|sum|product|length|count> [t]
diff --git a/bench/ill-hit.hs b/bench/ill-hit.hs
--- a/bench/ill-hit.hs
+++ b/bench/ill-hit.hs
@@ -38,8 +38,8 @@
 
 ingredients :: [Ingredient]
 ingredients =
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
+  [ con (0 :: Int)
+  , con (1 :: Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
   , fun "null" (null :: [Int] -> Bool)
diff --git a/bench/ill-hit.txt b/bench/ill-hit.txt
--- a/bench/ill-hit.txt
+++ b/bench/ill-hit.txt
@@ -9,7 +9,7 @@
 -- 1 candidates of size 3
 -- 2 candidates of size 4
 -- 7 candidates of size 5
--- tested 7 candidates
+-- tested 11 candidates
 sum []  =  0
 sum (x:xs)  =  x + sum xs
 
@@ -20,7 +20,7 @@
 -- 3 candidates of size 3
 -- 10 candidates of size 4
 -- 18 candidates of size 5
--- tested 21 candidates
+-- tested 33 candidates
 sum []  =  0
 sum (x:xs)  =  x + sum xs
 
diff --git a/bench/p12.hs b/bench/p12.hs
deleted file mode 100644
--- a/bench/p12.hs
+++ /dev/null
@@ -1,71 +0,0 @@
--- 12 background ingredients
---
--- Copyright (C) 2021-2025 Rudy Matela
--- Distributed under the 3-Clause BSD licence (see the file LICENSE).
-import Conjure
-import System.Environment
-
-factorial :: Int -> Int
-factorial 0  =  1
-factorial 1  =  1
-factorial 2  =  2
-factorial 3  =  6
-factorial 4  =  24
-factorial 5  =  120
-
-count' :: Int -> [Int] -> Int
-count' 0 [0]  =  1
-count' 0 [1]  =  0
-count' 1 [0]  =  0
-count' 1 [1]  =  1
-count' 0 [0,0]  =  2
-count' 0 [0,1]  =  1
-count' 0 [1,2]  =  0
-count' 1 [0,0]  =  0
-count' 1 [0,1]  =  1
-count' 1 [1,2]  =  1
-count' 0 [0,0,0]  =  3
-count' 0 [0,0,1]  =  2
-count' 0 [1,0,0]  =  2
-
-main :: IO ()
-main  =  do
-  putStrLn $ "running with " ++ show (length ingredients) ++ " ingredients"
-  as <- getArgs
-  case as of
-    ["factorial"]     -> conjure "factorial n" factorial   ingredients
-    ["factorial","t"] -> conjure "factorial n" factorial $ ingredients ++ [maxSize 1]
-    ["sum"]           -> conjure "sum"     (sum     :: [Int] -> Int)   ingredients
-    ["sum","t"]       -> conjure "sum"     (sum     :: [Int] -> Int) $ ingredients ++ [maxSize 1]
-    ["product"]       -> conjure "product" (product :: [Int] -> Int)   ingredients
-    ["product","t"]   -> conjure "product" (product :: [Int] -> Int) $ ingredients ++ [maxSize 1]
-    ["length"]        -> conjure "length"  (length  :: [Int] -> Int)   ingredients
-    ["length","t"]    -> conjure "length"  (length  :: [Int] -> Int) $ ingredients ++ [maxSize 1]
-    ["count"]         -> conjure "count"   count' $ ingredients ++ primsCount
-    ["count","t"]     -> conjure "count"   count' $ ingredients ++ primsCount ++ [maxSize 1]
-    _                 -> conjure "factorial n" factorial ingredients
-
-ingredients :: [Ingredient]
-ingredients  =
-  [ unfun (0::Int)
-  , unfun (1::Int)
-  , fun "+" ((+) :: Int -> Int -> Int)
-  , fun "*" ((*) :: Int -> Int -> Int)
-  , fun "dec" (subtract 1 :: Int -> Int)
-
-  , fun "==" ((==) :: Int -> Int -> Bool)
-
-  , unfun ([] :: [Int])
-  , fun ":" ((:) :: Int -> [Int] -> [Int])
-  , fun "head" (head :: [Int] -> Int)
-  , fun "tail" (tail :: [Int] -> [Int])
-  , fun "null" (null :: [Int] -> Bool)
-  , fun "foldr" (foldr :: (Int -> Int -> Int) -> Int -> [Int] -> Int)
-  , fun ".." (enumFromTo :: Int -> Int -> [Int])
-  ]
-
-primsCount :: [Ingredient]
-primsCount  =
-  [ fun "length" (length :: [Int] -> Int)
-  , fun "filter" (filter :: (Int -> Bool) -> [Int] -> [Int])
-  ]
diff --git a/bench/p12.txt b/bench/p12.txt
deleted file mode 100644
--- a/bench/p12.txt
+++ /dev/null
@@ -1,14 +0,0 @@
-running with 13 ingredients
-factorial :: Int -> Int
--- testing 6 combinations of argument values
--- pruning with 67/101 rules
--- 3 candidates of size 1
--- 3 candidates of size 2
--- 6 candidates of size 3
--- 13 candidates of size 4
--- 40 candidates of size 5
--- 138 candidates of size 6
--- tested 69 candidates
-factorial 0  =  1
-factorial x  =  x * factorial (dec x)
-
diff --git a/bench/p30.hs b/bench/p30.hs
deleted file mode 100644
--- a/bench/p30.hs
+++ /dev/null
@@ -1,87 +0,0 @@
--- 30 background ingredients, does Conjure scale?
---
--- Copyright (C) 2021-2025 Rudy Matela
--- Distributed under the 3-Clause BSD licence (see the file LICENSE).
-import Conjure
-import System.Environment
-
-factorial :: Int -> Int
-factorial 0  =  1
-factorial 1  =  1
-factorial 2  =  2
-factorial 3  =  6
-factorial 4  =  24
-factorial 5  =  120
-
-count' :: Int -> [Int] -> Int
-count' 0 [0]  =  1
-count' 0 [1]  =  0
-count' 1 [0]  =  0
-count' 1 [1]  =  1
-count' 0 [0,0]  =  2
-count' 0 [0,1]  =  1
-count' 0 [1,2]  =  0
-count' 1 [0,0]  =  0
-count' 1 [0,1]  =  1
-count' 1 [1,2]  =  1
-count' 0 [0,0,0]  =  3
-count' 0 [0,0,1]  =  2
-count' 0 [1,0,0]  =  2
-
-main :: IO ()
-main  =  do
-  putStrLn $ "running with " ++ show (length ingredients) ++ " ingredients"
-  as <- getArgs
-  case as of
-    ["factorial"]     -> conjure "factorial n" factorial   ingredients
-    ["factorial","t"] -> conjure "factorial n" factorial $ ingredients ++ [maxSize 1]
-    ["sum"]           -> conjure "sum"     (sum     :: [Int] -> Int)   ingredients
-    ["sum","t"]       -> conjure "sum"     (sum     :: [Int] -> Int) $ ingredients ++ [maxSize 1]
-    ["product"]       -> conjure "product" (product :: [Int] -> Int)   ingredients
-    ["product","t"]   -> conjure "product" (product :: [Int] -> Int) $ ingredients ++ [maxSize 1]
-    ["length"]        -> conjure "length"  (length  :: [Int] -> Int)   ingredients
-    ["length","t"]    -> conjure "length"  (length  :: [Int] -> Int) $ ingredients ++ [maxSize 1]
-    ["count"]         -> conjure "count"   count' $ ingredients ++ primsLength
-    ["count","t"]     -> conjure "count"   count' $ ingredients ++ primsLength ++ [maxSize 1]
-    _                 -> putStrLn "usage: p30 <factorial|sum|product|length|count> [t]"
-
-ingredients :: [Ingredient]
-ingredients  =
-  [ unfun False
-  , unfun True
-  , fun "&&" (&&)
-  , fun "||" (||)
-  , fun "not" not
-
-  , unfun (0::Int)
-  , unfun (1::Int)
-  , fun "+" ((+) :: Int -> Int -> Int)
-  , fun "*" ((*) :: Int -> Int -> Int)
-  , fun "dec" (subtract 1 :: Int -> Int)
-  , fun "-" ((-) :: Int -> Int -> Int)
-
-  , fun "==" ((==) :: Int -> Int -> Bool)
-  , fun "<=" ((<=) :: Int -> Int -> Bool)
-  , fun "<"  ((<) :: Int -> Int -> Bool)
-
-  , fun "const" (const :: Int -> Int -> Int)
-
-  , unfun ([] :: [Int])
-  , fun ":" ((:) :: Int -> [Int] -> [Int])
-  , fun "head" (head :: [Int] -> Int)
-  , fun "tail" (tail :: [Int] -> [Int])
-  , fun "null" (null :: [Int] -> Bool)
-  , fun "foldr" (foldr :: (Int -> Int -> Int) -> Int -> [Int] -> Int)
-
-  , fun "map" (map :: (Int -> Int) -> [Int] -> [Int])
-  , fun "filter" (filter :: (Int -> Bool) -> [Int] -> [Int])
-  , fun ".." (enumFromTo :: Int -> Int -> [Int])
-
-  , fun "++" ((++) :: [Int] -> [Int] -> [Int])
-  , fun "elem" (elem :: Int -> [Int] -> Bool)
-  ]
-
-primsLength :: [Ingredient]
-primsLength =
-  [ fun "length" (length :: [Int] -> Int)
-  ]
diff --git a/bench/p30.txt b/bench/p30.txt
deleted file mode 100644
--- a/bench/p30.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-running with 26 ingredients
-usage: p30 <factorial|sum|product|length|count> [t]
diff --git a/bench/psb2.hs b/bench/psb2.hs
new file mode 100644
--- /dev/null
+++ b/bench/psb2.hs
@@ -0,0 +1,851 @@
+-- gps2.hs: General Program Synthesis Benchmark Suite II
+--
+-- Copyright (C) 2021-2025 Rudy Matela
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+{-# LANGUAGE CPP, TemplateHaskell #-}
+import Conjure
+import System.Environment (getArgs)
+
+import Data.List (findIndex, inits)               -- for  #1
+import Data.Char (toUpper)                        -- for  #4
+import Data.Ratio ((%))                           -- for  #7
+import Data.List (findIndices, tails, isPrefixOf) -- for #12
+import Data.Maybe (fromJust)                      -- for #23
+import Test.LeanCheck                             -- for #24
+import Data.Express                               -- for #24
+
+
+-- PSB2 #1 -- Basement (AoC) ---
+-- Given a vector of integers, return the first index such that the sum of all
+-- integers from the start of the vector to the index (inclusive) is negative
+
+gps1p :: [Int] -> Maybe Int
+gps1p [0,-1,2]   =  Just 1
+gps1p [-1,0,1]   =  Just 0
+gps1p [0,-1]     =  Just 1
+gps1p [1,-1,-1]  =  Just 2
+
+gps1g :: [Int] -> Maybe Int
+gps1g xs  =  findIndex (0 >) (map sum (tail (inits xs)))
+
+gps1p2 :: Int -> [Int] -> Int
+gps1p2 0 [0,-1,2]   =  1
+gps1p2 0 [-1,0,1]   =  0
+gps1p2 0 [0,-1]     =  1
+gps1p2 0 [1,-1,-1]  =  2
+gps1p2 0 [0,0,0,-1]  =  3
+gps1p2 0 [1,0,0,-2]  =  3
+
+-- efficient gps1, unreachable performance-wise
+gps1g2 :: Int -> [Int] -> Int
+gps1g2 t []  =  undefined -- 1
+gps1g2 t (x:xs)  =  if t + x < 0 -- 7
+                    then 0 -- 8
+                    else 1 + gps1g2 (t + x) xs -- 15
+
+gps1c :: IO ()
+gps1c  =  do
+  conjure "gps1" gps1p
+    [ con (0 :: Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun ">" ((>) :: Int -> Int -> Bool)
+    , fun "foldr" (foldr :: (Int -> Int -> Int) -> Int -> [Int] -> Int)
+    , fun "sum" (sum :: [Int] -> Int)
+    , fun "findIndex" (findIndex :: (Int -> Bool) -> [Int] -> Maybe Int)
+    , fun "map" (map :: ([Int] -> Int) -> [[Int]] -> [Int])
+    , fun "inits" (inits :: [Int] -> [[Int]])
+    , fun "tail" (tail :: [[Int]] -> [[Int]])
+    ]
+
+  conjure "gps1" gps1p
+    [ con (0 :: Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun ">" ((>) :: Int -> Int -> Bool)
+    , fun "sum" (sum :: [Int] -> Int)
+    , fun "foldr" (foldr :: (Int -> Int -> Int) -> Int -> [Int] -> Int)
+    , fun "findIndex" (findIndex :: (Int -> Bool) -> [Int] -> Maybe Int)
+    , fun "map" (map :: ([Int] -> Int) -> [[Int]] -> [Int])
+    , fun "inits" (inits :: [Int] -> [[Int]])
+    , fun "tail" (tail :: [[Int]] -> [[Int]])
+    ]
+
+  conjure "gps1" gps1p2
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun "<" ((<) :: Int -> Int -> Bool)
+    , guard
+    , fun "undefined" (undefined :: Int)
+    , maxSize 4
+    , maxEquationSize 4
+    ]
+
+
+-- PSB2 #2 -- Bouncing Balls (CW) --
+
+gps2p :: Double -> Double -> Int -> Double
+gps2p 2 1 1  =  2 + 1
+gps2p 2 1 2  =  2 + 1 + 1 + 0.5
+gps2p 2 1 3  =  2 + 1 + 1 + 0.5 + 0.5 + 0.25
+gps2p 3 1 1  =  3 + 1
+gps2p 3 1 2  =  3 + 1 + 1/3
+
+-- apex to apex
+gps2g :: Double -> Double -> Int -> Double
+gps2g h0 h1 0  =  h0 + h1
+gps2g h0 h1 n  =  h0 + h1 + gps2g h1 (h1 * (h1 / h0)) (n - 1)
+-- size 17, out of reach performance-wise
+
+gps2c :: IO ()
+gps2c  =  do
+  conjure "gps2" gps2p
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , fun "*" ((*) :: Double -> Double -> Double)
+    , fun "/" ((/) :: Double -> Double -> Double)
+    , fun "+" ((+) :: Double -> Double -> Double)
+    , fun "-" ((-) :: Double -> Double -> Double)
+    , maxSize 6
+    ]
+
+
+gps3p :: String -> Int
+gps3p "X X X X X X X X X XXX"  =  300
+gps3p "11 11 11 11 11 11 11 11 11 11"  =  20
+
+-- unreachable performance wise
+-- I presume a correct solution would need around 30 symbols
+gps3c :: IO ()
+gps3c  =  conjure "gps3" gps3p []
+
+
+
+-- PSB2 #4: https://www.codewars.com/kata/517abf86da9663f1d2000003
+-- Here we're using the problem description as in the PSB2 paper
+-- considering we're getting input as kebab-case.
+-- Nevertheless, this one is out of reach performance-wise (and OOM-wise)
+
+gps4s :: (String -> String) -> [Property]
+gps4s g  =
+  [ property $ g "the-stealth-warrior" == "theStealthWarrior"
+  , property $ g "camel-case" == "camelCase"
+  , property $ g "Kebab-Case" == "KebabCase"
+  ]
+
+gps4g :: String -> String
+gps4g ""  =  ""
+-- gps4g ('-':c:cs)  =  toUpper c : gps4g cs
+-- gps4g ('_':c:cs)  =  toUpper c : gps4g cs
+gps4g (c:cs)  =  if c == '-'                                   --  5
+                 then if null cs                               --  8
+                      then ""                                  --  9
+                      else toUpper (head cs) : gps4g (tail cs) -- 16
+                 else c : gps4g cs                             -- 19
+
+gps4c :: IO ()
+gps4c  =  do
+  conjureFromSpec "gps4" gps4s
+    [ con '-'
+    , con ("" :: String)
+    , fun ":" ((:) :: Char -> String -> String)
+    , fun "==" ((==) :: Char -> Char -> Bool)
+    , fun "head" (head :: String -> Char)
+    , fun "tail" (tail :: String -> String)
+    , iif (undefined :: Char)
+    , iif (undefined :: String)
+    , fun "toUpper" (toUpper :: Char -> Char)
+    , maxSize 6
+    ]
+
+
+-- PSB2 #5: Coin Sums
+-- https://projecteuler.net/problem=31
+--
+-- The problem description is inconsistent with the one given in the paper.
+--
+-- Paper: change-making problem in USD
+-- Euler: How many different ways can £2 be made using any number of coins?
+--
+-- I'm considering the Paper to be canonical, as the one in Project Euler can be solved by a constant function:
+--
+-- solution :: Int
+-- solution  =  6378216738  -- <-- arbitrary example here, I didn't run the numbers
+gps5p :: Int -> [Int]
+gps5p 100  =  [4, 0, 0, 0]
+gps5p  50  =  [2, 0, 0, 0]
+gps5p  25  =  [1, 0, 0, 0]
+gps5p  30  =  [1, 0, 1, 0]
+gps5p  20  =  [0, 2, 0, 0]
+gps5p   3  =  [0, 0, 0, 3]
+
+gps5s :: ([Int] -> Int -> [Int]) -> [Property]
+gps5s t  =
+  [ property $ t [25, 10, 5, 1] 100 == [4, 0, 0, 0]
+  , property $ t [25, 10, 5, 1]  50 == [2, 0, 0, 0]
+  , property $ t [25, 10, 5, 1]  25 == [1, 0, 0, 0]
+  , property $ t [25, 10, 5, 1]  30 == [1, 0, 1, 0]
+  , property $ t [25, 10, 5, 1]  20 == [0, 2, 0, 0]
+  , property $ t [25, 10, 5, 1]   3 == [0, 0, 0, 3]
+  ]
+
+coins :: [Int]
+coins  =  [25, 10, 5, 1]
+
+gps5g :: Int -> [Int]
+gps5g  =  tell coins
+
+tell :: [Int] -> Int -> [Int]
+tell []     a  =  []
+tell (n:ns) a  =  a `div` n : tell ns (a `mod` n)
+
+gps5c :: IO ()
+gps5c  =  do
+  -- cannot conjure directly due to needing to introduce a local definition
+  conjure "gps5" gps5p
+    [
+    ]
+
+  conjureFromSpec "tell" gps5s
+    [ con ([] :: [Int])
+    , fun ":" ((:) :: Int -> [Int] -> [Int])
+    , fun "`div`" (div :: Int -> Int -> Int)
+    , fun "`mod`" (mod :: Int -> Int -> Int)
+    ]
+
+  conjure "gps5" gps5p
+    [ con coins
+    , fun "tell" tell
+    ]
+
+  conjure "gps5" gps5p
+    [ con (1 :: Int)
+    , con (5 :: Int)
+    , con (10 :: Int)
+    , con (25 :: Int)
+    , con ([] :: [Int])
+    , fun ":" ((:) :: Int -> [Int] -> [Int])
+    , fun "tell" tell
+    , target 50400
+    ]
+
+
+-- PSB2 #6: Cut Vector
+gps6g :: [Int] -> Int
+gps6g xs  =  snd
+          $  minimum
+          [  (abs (sum xs0 - sum xs1), i)
+          |  i <- [0 .. length xs]
+          ,  let (xs0, xs1) = splitAt i xs
+          ]
+
+-- not Conjurable due to needing local definition
+-- I conjecture it _perhaps-maybe_ this could be done in 3 steps,
+-- but I'll leave this as-is for now.
+gps6c :: IO ()
+gps6c  =
+  conjure "gps6" gps6g []
+
+
+-- PSB2 #7: Dice Game
+-- https://projecteuler.net/problem=31
+-- https://github.com/thelmuth/Clojush/blob/psb2-v1.0/src/clojush/problems/psb2/dice_game.clj
+-- again, paper and problem are inconsistent, going with paper
+gps7p :: Integer -> Integer -> Rational
+gps7p 4 6  =  1 % 4
+gps7p 6 4  =  7 % 12
+gps7p 2 4  =  1 % 8
+gps7p 4 2  =  5 % 8
+gps7p 2 6  =  1 % 12
+gps7p 6 2  =  3 % 4
+
+gps7g :: Integer -> Integer -> Rational
+gps7g peter colin  =  sum (map (min colin) [0 .. (peter-1)]) % (colin*peter)
+
+-- out of reach performance-wise
+gps7c :: IO ()
+gps7c  =  do
+  conjure "gps7" gps7p $ take 0
+    [ con (0 :: Integer)
+    , con (1 :: Integer)
+    , fun "%" ((%) :: Integer -> Integer -> Rational)
+    , fun "+" ((+) :: Integer -> Integer -> Integer)
+    , fun "-" ((-) :: Integer -> Integer -> Integer)
+    , fun "*" ((*) :: Integer -> Integer -> Integer)
+    , fun "min" (min :: Integer -> Integer -> Integer)
+    , fun ".." (enumFromTo :: Integer -> Integer -> [Integer])
+    , fun "map" (map :: (Integer -> Integer) -> [Integer] -> [Integer])
+    , fun "sum" (sum :: [Integer] -> Integer)
+    , maxSize 6
+    ]
+
+
+gps8p :: Int -> [Int] -> (Int,Int)
+gps8p 2 [1,1,2]  =  (1,1)
+gps8p 3 [1,1,2]  =  (1,2)
+gps8p 2 [0,1,0,2]  =  (0,2)
+
+gps8g :: Int -> [Int] -> (Int,Int)
+gps8g x xs  =  head [(y,z) | y <- xs, z <- xs, y + z == x]
+-- this one could be generated but is a bit of a stretch...
+-- it is unintuitive to provide the given symbols
+-- gps8g :: Int -> [Int] -> (Int,Int)
+-- gps8g x xs  =  head $ filter ((x ==) . uncurry (+)) $ liftA2 (,) xs xs
+
+gps8c :: IO ()
+gps8c  =  conjure "gps8" gps8p []
+
+
+-- PSB2 #9: Fizz Buzz (CW)
+gps9p :: Int -> String
+gps9p 3  =  "Fizz"
+gps9p 4  =  "4"
+gps9p 5  =  "Buzz"
+gps9p 6  =  "Fizz"
+gps9p 10  =  "Buzz"
+gps9p 15  =  "FizzBuzz"
+gps9p 17  =  "17"
+
+gps9g :: Int -> String
+gps9g x
+  | x `mod` 3 == 0  =  "Fizz" -- 7
+  | x `mod` 5 == 0  =  "Buzz" -- 14
+  | x `mod` 3 == 0 && x `mod` 5 == 0  =  "FizzBuzz" -- 27
+  | otherwise       =  show x -- 29
+
+-- unreachable performance-wise:
+-- too many candidates to sift through
+-- even in two steps
+gps9c :: IO ()
+gps9c  =  conjure "gps9" gps9p
+  [ con "Fizz"
+  , con "Buzz"
+  , con "FizzBuzz"
+  , con (0 :: Int)
+  , con (3 :: Int)
+  , con (5 :: Int)
+  , con False
+  , con True
+  , fun "`divBy`" divBy
+--, fun "`mod`" (mod :: Int -> Int -> Int)
+  , fun "&&" (&&)
+--, fun "==" ((==) :: Int -> Int -> Bool)
+  , fun "show" (show :: Int -> String)
+  , iif (undefined :: String)
+  , target 1080 -- so this fails quickly...
+  ]
+  where
+  -- two-step try:
+  divBy :: Int -> Int -> Bool
+  x `divBy` 0  =  False
+  x `divBy` y  =  x `mod` y == 0
+
+
+gps10p :: [Int] -> Int
+gps10p [0]  =  -2
+gps10p [3]  =  -1
+gps10p [6]  =  0
+gps10p [9]  =  1
+gps10p [0,3]  =  -3
+gps10p [3,0]  =  -3
+gps10p [3,2,1]  =  -5
+gps10p [1,2,3]  =  -5
+gps10p [10,20,30]  =  13
+
+-- does not do rounding
+gps10g :: [Int] -> Int
+gps10g []  =  0
+gps10g (x:xs)  =  (x `div` 3 - 2) + gps10g xs
+
+-- unreachable due to lambda
+gps10c :: IO ()
+gps10c  =  conjure "gps10" gps10p
+  [ con (0 :: Int)
+  , con (1 :: Int)
+  , con (2 :: Int)
+  , con (3 :: Int)
+  , fun "`div`" (div :: Int -> Int -> Int)
+  , fun "+" ((+) :: Int -> Int -> Int)
+  , fun "-" ((-) :: Int -> Int -> Int)
+  , target 50400
+  ]
+
+
+gps11p :: Int -> Int -> Int
+gps11p  =  gcd'
+  where
+  gcd' :: Int -> Int -> Int
+  gcd' 1 1  =  1
+  gcd' 1 2  =  1
+  gcd' 2 1  =  1
+  gcd' 2 2  =  2
+  gcd' 2 6  =  2
+  gcd' 6 2  =  2
+  gcd' 3 6  =  3
+  gcd' 6 3  =  3
+  gcd' 6 9  =  3
+  gcd' 9 6  =  3
+  gcd' 12 18  =  6
+
+gps11c :: IO ()
+gps11c  =  conjure "gcd a b" gps11p
+  [ con (0::Int)
+  , fun "`mod`" (mod :: Int -> Int -> Int)
+  ]
+  -- generated function:
+  -- gcd x 0  =  x
+  -- gcd x y  =  gcd y (x `mod` y)
+
+
+gps12p :: String -> String -> [Int]
+gps12p "a"   "a"   =  [0]
+gps12p "aa"  "a"   =  [0,1]
+gps12p "aa"  "aa"  =  [0]
+gps12p "a a" "a"   =  [0,2]
+gps12p "b"   "a"   =  []
+
+gps12g :: String -> String -> [Int]
+gps12g s s'  =  findIndices (s' `isPrefixOf`) (tails s)
+
+gps12c :: IO ()
+gps12c  =  conjure "gps12" gps12p
+  [ fun "findIndices" (findIndices :: (String -> Bool) -> [String] -> [Int])
+  , fun "`isPrefixOf`" (isPrefixOf :: String -> String -> Bool)
+  , fun "tails" (tails :: String -> [String])
+  ]
+
+
+gps13p :: [Int] -> [Int]
+gps13p [0,1]  =  [1]
+gps13p [1,0]  =  [1,0]
+gps13p [2,0,1]  =  [2,1]
+gps13p [1,0,1]  =  [1]
+
+gps13g :: [Int] -> [Int]
+gps13g  =  leaders
+  where
+  leaders []  =  []
+  leaders (x:xs)  =  if all (x >) xs
+                     then x : leaders xs
+                     else leaders xs
+
+gps13c :: IO ()
+gps13c  =  conjure "gps13_leaders" gps13p
+  [ con ([] :: [Int])
+  , fun ":" ((:) :: Int -> [Int] -> [Int])
+  , fun ">" ((>) :: Int -> Int -> Bool)
+  , fun "<" ((<) :: Int -> Int -> Bool)
+  , fun "all" (all :: (Int -> Bool) -> [Int] -> Bool)
+  , fun "any" (any :: (Int -> Bool) -> [Int] -> Bool)
+  , guard
+  ]
+
+
+gps14p :: [Int] -> Int
+gps14p  =  undefined
+
+-- 30 symbols
+gps14g :: [Int] -> Int
+gps14g  =  luhn
+  where
+  luhn :: [Int] -> Int
+  luhn xs  =  sum (firsts xs ++ map double9 (seconds xs))
+    where
+    double9 :: Int -> Int
+    double9 x  =  if xx > 9
+                  then xx - 9
+                  else xx
+      where
+      xx  =  x * 2
+    seconds :: [Int] -> [Int]
+    seconds []  =  []
+    seconds (x:y:xs)  =  y : seconds xs
+    firsts :: [Int] -> [Int]
+    firsts []  =  []
+    firsts (x:y:xs)  =  x : seconds xs
+
+-- cannot Conjure directly
+gps14c :: IO ()
+gps14c  =  conjure "gps14_luhn" gps14p
+  [
+  ]
+
+
+gps15p :: () -> ()
+gps15p  =  undefined
+
+-- skipped
+gps15c :: IO ()
+gps15c  =  conjure "gps15_mastermind" gps15p []
+
+
+gps16p :: String -> String
+gps16p "a"      =  "a"
+gps16p "aaa"    =  "a"
+gps16p "aa"     =  "aa"
+gps16p "a a"    =  " "
+gps16p " a "    =  "a"
+gps16p "a a "   =  " a"
+gps16p " a a "  =  " "
+gps16p "aba"    =  "b"
+gps16p "bab"    =  "a"
+gps16p "abba"   =  "bb"
+gps16p "aaaaa"  =  "a"
+
+gps16g1 :: String -> String
+gps16g1 s  =  if odd len
+              then take 1 (drop (len `div` 2) s)
+              else take 2 (drop (len `div` 2 - 1) s)
+  where
+  len  =  length s
+
+gps16g2 :: String -> String
+gps16g2 ""  =  ""
+gps16g2 (c:cs)  =  if length cs <= 1
+                   then c : cs
+                   else gps16g2 (init cs)
+
+gps16c :: IO ()
+gps16c  =  conjure "gps16_middle" gps16p
+  [ con ""
+  , con (1 :: Int)
+  , fun "<=" ((<=) :: Int -> Int -> Bool)
+  , fun ":" ((:) :: Char -> String -> String)
+  , fun "length" (length :: String -> Int)
+  , fun "init" (init :: String -> String)
+  , iif (undefined :: String) -- TODO: can't replace by guard, why? (July 2025)
+  -- update: it is enumerated, but somehow does not passes the tests, why?
+  ]
+
+
+-- PSB2 #17 -- Paired Digits (AoC) --
+-- Given a string of digits,
+-- return the sum of the digits
+-- whose following digit are the same.
+-- Originally called "Inverse Captcha":
+-- https://adventofcode.com/2017/day/1
+
+gps17p :: [Int] -> Int
+gps17p [0,1,0]  =  0
+gps17p [1,1]  =  1
+gps17p [0,0,1,1]  =  1
+gps17p [1,1,0]  =  1
+gps17p [0,1,1]  =  1
+gps17p [1,1,1]  =  2
+gps17p [0,1,2]  =  0
+gps17p [1,1,2,2]  =  3
+gps17p [1,1,1,1]  =  3  -- variation from advent
+gps17p [1,2,3,4]  =  0
+
+gps17g :: [Int] -> Int
+gps17g xs  =  pds xs
+  where
+  pds []  =  0
+  pds (x:xs)  =  if not (null xs) && x == head xs
+                 then x + pds xs
+                 else pds xs
+-- surprise:
+-- gps17_pds []  =  0
+-- gps17_pds (x:xs)  =  (if not (null xs) && head xs == x then x else 0) + gps17_pds xs
+
+
+-- can generate at size 15 in 6
+-- setting limit of 5 for faster automated tests
+-- BENCHMARK: increase maxSize from 6 to 18
+gps17c :: IO ()
+gps17c  =  do
+  conjure "gps17_pds" gps17p
+    [ con (0 :: Int)
+    , guard
+    , fun "not" not
+    , fun "null" (null :: [Int] -> Bool)
+    , fun "==" ((==) :: Int -> Int -> Bool)
+    , fun "head" (head :: [Int] -> Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun "&&" (&&)
+    , maxSize 6 -- 18
+    ]
+
+  -- OOM after size 16, unreachable by increasing pattern depth
+  conjure "gps17_pds" gps17p
+    [ con (0 :: Int)
+    , guard
+    , fun "==" ((==) :: Int -> Int -> Bool)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , maxPatternDepth 2
+    , maxSize 6 -- 18
+    ]
+
+
+gps18p :: [Double] -> [Double] -> Double
+gps18p [1.0] [0.5]  =  0.5
+gps18p [2.0] [0.5]  =  1.0
+gps18p [1.0,1.0] [0.5,0.0]  =  1.5
+gps18p [1.0,1.0] [0.0,0.5]  =  1.5
+
+gps18g :: [Double] -> [Double] -> Double
+gps18g prices discounts  =  foldr (+) 0 (zipWith (*) prices (map (1-) discounts))
+
+-- this was OOM'd
+gps18c :: IO ()
+gps18c  =  conjure "gps18_price" gps18p
+  [ con (0 :: Double)
+  , con (1 :: Double)
+  , fun "+" ((+) :: Double -> Double -> Double)
+  , fun "*" ((*) :: Double -> Double -> Double)
+  , fun "-" ((-) :: Double -> Double -> Double)
+--  , fun "foldr" (foldr :: (Double -> Double -> Double) -> Double -> [Double] -> Double)
+--   , fun "zipWith" (zipWith :: (Double -> Double -> Double) -> [Double] -> [Double] -> [Double])
+--  , fun "map" (map :: (Double -> Double) -> [Double] -> [Double])
+  , maxSize 6
+  ]
+
+
+gps19p :: Int -> Double -> Double -> Double -> Double
+gps19p 0 0 1.0 1.0  =  0
+gps19p 1 0 1.0 1.0  =  0
+gps19p 2 0 1.0 1.0  =  0
+gps19p 1 0 1.0 2.0  =  1.0
+gps19p 2 0 1.0 2.0  =  2.0
+gps19p 1 0 0.5 1.0  =  0.5
+gps19p 2 0 0.5 1.0  =  1.0
+
+gps19g :: Int -> Double -> Double -> Double -> Double
+gps19g 0 total melt fall  =  total
+gps19g n total melt fall  =  gps19p (n-1) (max 0 (total-melt+fall)) melt fall
+-- size 14, out of reach performance wise.
+
+gps19c :: IO ()
+gps19c  =  conjure "gps19_snowday" gps19p
+  [ con (0 :: Int)
+  , con (1 :: Int)
+  , fun "max" (max :: Double -> Double -> Double)
+  , fun "+" ((+) :: Double -> Double -> Double)
+  , fun "-" ((-) :: Double -> Double -> Double)
+  , maxSize 6
+  ]
+
+
+gps20p :: String -> Bool
+gps20p  =  undefined
+
+gps20c :: IO ()
+gps20c  =  conjure "gps20" gps20p
+  [
+  ]
+
+
+gps21s :: (String -> String) -> [Property]
+gps21s s  =
+  [ property $ s "word" == "word"
+  , property $ s "words" == "sdrow"
+  , property $ s "word words" == "word sdrow"
+  , property $ s "words word" == "sdrow word"
+  ]
+
+spinSpec :: (String -> String) -> [Property]
+spinSpec spin  =
+  [ property $ spin "abc" == "abc"
+  , property $ spin "abcd" == "abcd"
+  , property $ spin "word" == "word"
+  , property $ spin "abcde" == "edcba"
+  , property $ spin "words" == "sdrow"
+  , property $ spin "hello" == "olleh"
+  , property $ spin "world" == "dlrow"
+  ]
+
+spin :: String -> String
+spin w  =  if length w >= 5
+           then reverse w
+           else w
+
+gps21g :: String -> String
+gps21g s  =  unwords (map spin (words s))
+
+gps21c :: IO ()
+gps21c  =  do
+  conjureFromSpec "spin" spinSpec
+    [ fun "length"  (length :: String -> Int)
+    , fun "reverse" (reverse :: String -> String)
+    , guard
+    , fun ">="      ((>=) :: Int -> Int -> Bool)
+    , con (5 :: Int)
+    ]
+
+  conjureFromSpec "gps21_spinwords" gps21s
+    [ fun "words"   words
+    , fun "unwords" unwords
+    , fun "spin"    (spin :: String -> String)
+    , fun "map"     (map :: (String -> String) -> [String] -> [String])
+    , fun "length"  (length :: String -> Int)
+    , fun "reverse" (reverse :: String -> String)
+    , guard
+    , fun ">="      ((>=) :: Int -> Int -> Bool)
+    , con (5 :: Int)
+    ]
+
+
+-- PSB2 #22 -- Square Digits (CW) --
+-- Given a positive integer, square each digit and
+-- concatenate the squares into a returned string.
+
+gps22p :: Int -> String
+gps22p 1  =  "1"
+gps22p 12  =  "14"
+gps22p 21  =  "41"
+gps22p 123  =  "149"
+gps22p 321  =  "941"
+gps22p 1234  =  "14916"
+gps22p 4321  =  "16941"
+
+-- unreachable as-is
+-- reachable with auxiliary functions: div10, mod10 and square
+gps22g :: Int -> String
+gps22g 0  =  ""  -- 1
+gps22g x  =  gps22g (x `div` 10) ++ show (x `mod` 10 * x `mod` 10)  -- 14
+-- gps22g x  =  gps22g (x `div` 10) ++ show ((x `mod` 10) ^ 2)  -- 12
+
+gps22c :: IO ()
+gps22c  =  do
+  conjure "gps22" gps22p
+    [ con (0 :: Int)
+
+    -- uncomment the following four for the a runtime of 15s @ size 11
+    -- , con (10 :: Int)
+    -- , fun "`div`" (div :: Int -> Int -> Int)
+    -- , fun "`mod`" (mod :: Int -> Int -> Int)
+    -- , fun "square" ((^2) :: Int -> Int)
+    , fun "div10" ((`div` 10) :: Int -> Int)
+    , fun "mod10" ((`mod` 10) :: Int -> Int)
+    , fun "*" ((*) :: Int -> Int -> Int)
+
+    , fun "show" (show :: Int -> String)
+    , con ""
+    , fun "++" ((++) :: String -> String -> String)
+    ]
+
+
+gps23s :: (String -> String -> String -> String) -> [Property]
+gps23s s  =
+  [ property $ s "abcd" "abcd" "abcd" == "abcd"
+  , property $ s "abcd" "dcba" "abcd" == "dcba"
+  , property $ s "abcd" "1234" "abcd" == "1234"
+  , property $ s "abcd" "1234" "bacd" == "2134"
+  ]
+
+gps23g :: String -> String -> String -> String
+-- gps23g f t s  =  map (\c -> fromJust $ c `lookup` zipWith (,) f t) s
+gps23g f t s  =  map (fromJust . (`lookup` zipWith (,) f t)) s
+
+gps23c :: IO ()
+gps23c  =  do
+  -- cannot conjure, needs lambda
+  conjureFromSpec "gps23" gps23s
+    [
+    ]
+
+
+data Twitter  =  Tweet Int
+              |  TooMany
+              |  Empty
+              deriving (Eq, Show)
+
+deriveExpress  ''Twitter
+deriveListable ''Twitter
+deriveName     ''Twitter
+
+instance Conjurable Twitter where
+  conjureExpress   =  reifyExpress
+  conjureEquality  =  reifyEquality
+  conjureTiers     =  reifyTiers
+
+gps24g_twitter :: String -> Twitter
+gps24g_twitter ""  =  Empty
+gps24g_twitter s  =  if length s > 140
+                     then TooMany
+                     else Tweet (length s)
+
+gps24s_twitter :: (String -> Twitter) -> [Property]
+gps24s_twitter twitter  =
+  [ property $ twitter "" == Empty
+  , property $ twitter "abcd" == Tweet 4
+  , property $ twitter "0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij" == Tweet 140
+  , property $ twitter "0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghij0123456789abcdefghijX" == TooMany
+  ]
+
+gps24c :: IO ()
+gps24c  =  do
+  conjureFromSpec "gps24" gps24s_twitter
+    [ con Empty
+    , con TooMany
+    , fun "Tweet" Tweet
+    , guard
+    , con ""
+    , fun ":" ((:) :: Char -> String -> String)
+    , fun "length" (length :: String -> Int)
+    , con (140 :: Int)
+    , fun ">" ((>) :: Int -> Int -> Bool)
+    ]
+
+
+gps25p :: [Double] -> [Double] -> Double
+gps25p [0] [1]  =  1
+gps25p [1] [0]  =  1
+gps25p [-1] [1]  =  2
+gps25p [0,1] [1,0]  =  sqrt 2
+gps25p [1,0] [0,1]  =  sqrt 2
+gps25p [0,0,1] [1,0,0]  =  sqrt 2
+gps25p [0,1,2] [1,2,3]  =  sqrt 3
+
+gps25g :: [Double] -> [Double] -> Double
+gps25g v1 v2  =  sqrt (foldr (+) 0 (map (^2) (zipWith (-) v1 v2)))
+
+-- out of reach performance-wise
+gps25c :: IO ()
+gps25c  =  conjure "gps25" gps25p
+  [ con (0 :: Double)
+  , con (2 :: Double)
+  , fun "+" ((+) :: Double -> Double -> Double)
+  , fun "-" ((-) :: Double -> Double -> Double)
+  , fun "**" ((**) :: Double -> Double -> Double)
+  , fun "zipWith" (zipWith :: (Double -> Double -> Double) -> [Double] -> [Double] -> [Double])
+  , fun "map" (map :: (Double -> Double) -> [Double] -> [Double])
+  , fun "sqrt" (sqrt :: Double -> Double)
+  , maxSize 6
+  ]
+
+
+main :: IO ()
+main  =  do
+  as <- getArgs
+  case as of
+    [] -> sequence_ gpss
+    (n:_) -> gpss !! (read n - 1)
+
+
+gpss :: [IO ()]
+gpss  =  [ gps1c
+         , gps2c
+         , gps3c
+         , gps4c
+         , gps5c
+         , gps6c
+         , gps7c
+         , gps8c
+         , gps9c
+         , gps10c
+         , gps11c
+         , gps12c
+         , gps13c
+         , gps14c
+         , gps15c
+         , gps16c
+         , gps17c
+         , gps18c
+         , gps19c
+         , gps20c
+         , gps21c
+         , gps22c
+         , gps23c
+         , gps24c
+         , gps25c
+         ]
diff --git a/bench/psb2.txt b/bench/psb2.txt
new file mode 100644
--- /dev/null
+++ b/bench/psb2.txt
@@ -0,0 +1,388 @@
+gps1 :: [Int] -> Maybe Int
+-- testing 4 combinations of argument values
+-- pruning with 11/21 rules
+-- 0 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 1 candidates of size 4
+-- 0 candidates of size 5
+-- 0 candidates of size 6
+-- 1 candidates of size 7
+-- 0 candidates of size 8
+-- 1 candidates of size 9
+-- 2 candidates of size 10
+-- tested 4 candidates
+gps1 xs  =  findIndex (0 >) (map (foldr (+) 0) (tail (inits xs)))
+
+gps1 :: [Int] -> Maybe Int
+-- testing 4 combinations of argument values
+-- pruning with 11/21 rules
+-- 0 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 1 candidates of size 4
+-- 1 candidates of size 5
+-- 0 candidates of size 6
+-- 1 candidates of size 7
+-- 4 candidates of size 8
+-- tested 4 candidates
+gps1 xs  =  findIndex (0 >) (map sum (tail (inits xs)))
+
+gps1 :: Int -> [Int] -> Int
+-- testing 6 combinations of argument values
+-- pruning with 8/9 rules
+-- 4 candidates of size 1
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- 5 candidates of size 4
+-- tested 12 candidates
+gps1  =  undefined  -- search exhausted
+
+gps2 :: Double -> Double -> Int -> Double
+-- testing 5 combinations of argument values
+-- pruning with 2/6 rules
+-- 2 candidates of size 1
+-- 0 candidates of size 2
+-- 16 candidates of size 3
+-- 0 candidates of size 4
+-- 252 candidates of size 5
+-- 0 candidates of size 6
+-- tested 270 candidates
+gps2  =  undefined  -- search exhausted
+
+gps3 :: [Char] -> Int
+gps3  =  error "could not reify specification, suggestion: conjureFromSpec"
+
+gps4 :: [Char] -> [Char]
+-- pruning with 13/21 rules
+-- 2 candidates of size 1
+-- 3 candidates of size 2
+-- 8 candidates of size 3
+-- 20 candidates of size 4
+-- 51 candidates of size 5
+-- 119 candidates of size 6
+-- tested 203 candidates
+gps4  =  undefined  -- search exhausted
+
+gps5 :: Int -> [Int]
+-- testing 6 combinations of argument values
+-- pruning with 0/0 rules
+-- 0 candidates of size 1
+-- tested 0 candidates
+gps5  =  undefined  -- search exhausted
+
+tell :: [Int] -> Int -> [Int]
+-- pruning with 0/0 rules
+-- 2 candidates of size 1
+-- 1 candidates of size 2
+-- 2 candidates of size 3
+-- 6 candidates of size 4
+-- 6 candidates of size 5
+-- 39 candidates of size 6
+-- 26 candidates of size 7
+-- 328 candidates of size 8
+-- 134 candidates of size 9
+-- 3229 candidates of size 10
+-- tested 3476 candidates
+tell [] x  =  []
+tell (x:xs) y  =  y `div` x:tell xs (y `mod` x)
+
+gps5 :: Int -> [Int]
+-- testing 6 combinations of argument values
+-- pruning with 0/0 rules
+-- 1 candidates of size 1
+-- 0 candidates of size 2
+-- 1 candidates of size 3
+-- tested 2 candidates
+gps5  =  tell [25,10,5,1]
+
+gps5 :: Int -> [Int]
+-- testing 6 combinations of argument values
+-- pruning with 12/12 rules
+-- 1 candidates of size 1
+-- 0 candidates of size 2
+-- 5 candidates of size 3
+-- 0 candidates of size 4
+-- 35 candidates of size 5
+-- 0 candidates of size 6
+-- 350 candidates of size 7
+-- 0 candidates of size 8
+-- 3500 candidates of size 9
+-- 0 candidates of size 10
+-- 35000 candidates of size 11
+-- tested 21147 candidates
+gps5  =  tell [25,10,5,1]
+
+gps6 :: [Int] -> Int
+-- testing 360 combinations of argument values
+-- pruning with 0/0 rules
+-- 0 candidates of size 1
+-- 0 candidates of size 2
+-- tested 0 candidates
+gps6  =  undefined  -- search exhausted
+
+gps7 :: Integer -> Integer -> Ratio Integer
+-- testing 6 combinations of argument values
+-- pruning with 0/0 rules
+-- 0 candidates of size 1
+-- tested 0 candidates
+gps7  =  undefined  -- search exhausted
+
+gps8 :: Int -> [Int] -> (Int,Int)
+-- testing 3 combinations of argument values
+-- pruning with 0/0 rules
+-- 0 candidates of size 1
+-- 0 candidates of size 2
+-- tested 0 candidates
+gps8  =  undefined  -- search exhausted
+
+gps9 :: Int -> [Char]
+-- testing 7 combinations of argument values
+-- pruning with 18/25 rules
+-- 3 candidates of size 1
+-- 4 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 48 candidates of size 6
+-- 192 candidates of size 7
+-- 96 candidates of size 8
+-- 0 candidates of size 9
+-- 168 candidates of size 10
+-- 2976 candidates of size 11
+-- tested 3487 candidates
+gps9  =  undefined  -- search exhausted
+
+gps10 :: [Int] -> Int
+-- testing 7 combinations of argument values
+-- pruning with 67/100 rules
+-- 4 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 80 candidates of size 5
+-- 8 candidates of size 6
+-- 1428 candidates of size 7
+-- 432 candidates of size 8
+-- 30712 candidates of size 9
+-- tested 4552 candidates
+gps10 []  =  0
+gps10 (x:xs)  =  (x `div` 3 - 2) + gps10 xs
+
+gcd :: Int -> Int -> Int
+-- testing 11 combinations of argument values
+-- pruning with 0/0 rules
+-- 3 candidates of size 1
+-- 0 candidates of size 2
+-- 8 candidates of size 3
+-- 0 candidates of size 4
+-- 48 candidates of size 5
+-- 28 candidates of size 6
+-- tested 63 candidates
+gcd x 0  =  x
+gcd x y  =  gcd y (x `mod` y)
+
+gps12 :: [Char] -> [Char] -> [Int]
+-- testing 5 combinations of argument values
+-- pruning with 1/2 rules
+-- 0 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 4 candidates of size 5
+-- tested 3 candidates
+gps12 cs ds  =  findIndices (ds `isPrefixOf`) (tails cs)
+
+gps13_leaders :: [Int] -> [Int]
+-- testing 4 combinations of argument values
+-- pruning with 9/9 rules
+-- 2 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 0 candidates of size 6
+-- 0 candidates of size 7
+-- 0 candidates of size 8
+-- 11 candidates of size 9
+-- 16 candidates of size 10
+-- 53 candidates of size 11
+-- 48 candidates of size 12
+-- tested 101 candidates
+gps13_leaders []  =  []
+gps13_leaders (x:xs)
+  | all (x >) xs  =  x:gps13_leaders xs
+  | otherwise  =  gps13_leaders xs
+
+gps14_luhn :: [Int] -> Int
+gps14_luhn  =  error "could not reify specification, suggestion: conjureFromSpec"
+
+gps15_mastermind :: () -> ()
+gps15_mastermind  =  error "could not reify specification, suggestion: conjureFromSpec"
+
+gps16_middle :: [Char] -> [Char]
+-- testing 11 combinations of argument values
+-- pruning with 10/11 rules
+-- 2 candidates of size 1
+-- 2 candidates of size 2
+-- 2 candidates of size 3
+-- 3 candidates of size 4
+-- 5 candidates of size 5
+-- 8 candidates of size 6
+-- 17 candidates of size 7
+-- 50 candidates of size 8
+-- 145 candidates of size 9
+-- 391 candidates of size 10
+-- 993 candidates of size 11
+-- 2480 candidates of size 12
+-- tested 3719 candidates
+gps16_middle ""  =  ""
+gps16_middle (c:cs)  =  if length cs <= 1
+                        then c:cs
+                        else gps16_middle (init cs)
+
+gps17_pds :: [Int] -> Int
+-- testing 9 combinations of argument values
+-- pruning with 29/40 rules
+-- 1 candidates of size 1
+-- 1 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 2 candidates of size 5
+-- 4 candidates of size 6
+-- tested 8 candidates
+gps17_pds  =  undefined  -- search exhausted
+
+gps17_pds :: [Int] -> Int
+-- testing 9 combinations of argument values
+-- pruning with 13/19 rules
+-- 1 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 1 candidates of size 4
+-- 4 candidates of size 5
+-- 8 candidates of size 6
+-- tested 14 candidates
+gps17_pds  =  undefined  -- search exhausted
+
+gps18_price :: [Double] -> [Double] -> Double
+-- testing 4 combinations of argument values
+-- pruning with 26/35 rules
+-- 2 candidates of size 1
+-- 0 candidates of size 2
+-- 2 candidates of size 3
+-- 0 candidates of size 4
+-- 33 candidates of size 5
+-- 176 candidates of size 6
+-- tested 213 candidates
+gps18_price  =  undefined  -- search exhausted
+
+gps19_snowday :: Int -> Double -> Double -> Double -> Double
+-- testing 7 combinations of argument values
+-- pruning with 6/19 rules
+-- 3 candidates of size 1
+-- 0 candidates of size 2
+-- 21 candidates of size 3
+-- 0 candidates of size 4
+-- 309 candidates of size 5
+-- 0 candidates of size 6
+-- tested 333 candidates
+gps19_snowday  =  undefined  -- search exhausted
+
+gps20 :: [Char] -> Bool
+gps20  =  error "could not reify specification, suggestion: conjureFromSpec"
+
+spin :: [Char] -> [Char]
+-- pruning with 6/6 rules
+-- reasoning produced 1 incorrect properties, please re-run with more tests for faster results
+-- 1 candidates of size 1
+-- 1 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 0 candidates of size 6
+-- 0 candidates of size 7
+-- 4 candidates of size 8
+-- tested 6 candidates
+spin cs
+  | length cs >= 5  =  reverse cs
+  | otherwise  =  cs
+
+gps21_spinwords :: [Char] -> [Char]
+-- pruning with 16/16 rules
+-- reasoning produced 2 incorrect properties, please re-run with more tests for faster results
+-- 1 candidates of size 1
+-- 2 candidates of size 2
+-- 2 candidates of size 3
+-- 3 candidates of size 4
+-- 5 candidates of size 5
+-- tested 12 candidates
+gps21_spinwords cs  =  unwords (map spin (words cs))
+
+gps22 :: Int -> [Char]
+-- testing 7 combinations of argument values
+-- pruning with 13/17 rules
+-- 1 candidates of size 1
+-- 2 candidates of size 2
+-- 2 candidates of size 3
+-- 3 candidates of size 4
+-- 10 candidates of size 5
+-- 20 candidates of size 6
+-- 45 candidates of size 7
+-- 117 candidates of size 8
+-- 273 candidates of size 9
+-- 645 candidates of size 10
+-- 1567 candidates of size 11
+-- tested 2609 candidates
+gps22 0  =  ""
+gps22 x  =  gps22 (div10 x) ++ show (mod10 x * mod10 x)
+
+gps23 :: [Char] -> [Char] -> [Char] -> [Char]
+-- pruning with 0/0 rules
+-- 3 candidates of size 1
+-- 12 candidates of size 2
+-- 33 candidates of size 3
+-- 36 candidates of size 4
+-- 127 candidates of size 5
+-- 507 candidates of size 6
+-- 839 candidates of size 7
+-- 784 candidates of size 8
+-- 600 candidates of size 9
+-- 2722 candidates of size 10
+-- 5292 candidates of size 11
+-- tested 10955 candidates
+gps23  =  undefined  -- search exhausted
+
+gps24 :: [Char] -> Twitter
+-- pruning with 4/8 rules
+-- reasoning produced 4 incorrect properties, please re-run with more tests for faster results
+-- 2 candidates of size 1
+-- 3 candidates of size 2
+-- 6 candidates of size 3
+-- 6 candidates of size 4
+-- 3 candidates of size 5
+-- 5 candidates of size 6
+-- 10 candidates of size 7
+-- 48 candidates of size 8
+-- 134 candidates of size 9
+-- 216 candidates of size 10
+-- 308 candidates of size 11
+-- 466 candidates of size 12
+-- tested 803 candidates
+gps24 ""  =  Empty
+gps24 (c:cs)
+  | 140 > length cs  =  Tweet (length (c:cs))
+  | otherwise  =  TooMany
+
+gps25 :: [Double] -> [Double] -> Double
+-- testing 6 combinations of argument values
+-- pruning with 31/59 rules
+-- 2 candidates of size 1
+-- 1 candidates of size 2
+-- 5 candidates of size 3
+-- 10 candidates of size 4
+-- 76 candidates of size 5
+-- 438 candidates of size 6
+-- tested 532 candidates
+gps25  =  undefined  -- search exhausted
+
diff --git a/bench/redundants.hs b/bench/redundants.hs
--- a/bench/redundants.hs
+++ b/bench/redundants.hs
@@ -66,43 +66,43 @@
   -- We can also customize the n per-function below:
 
   printRedundantCandidates (n+1) "foo" (undefined :: Int -> Int)
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
 
   printRedundantCandidates n "?" (undefined :: Int -> Int -> Int)
-    [ unfun (0 :: Int)
+    [ con (0 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "dec" (subtract 1 :: Int -> Int)
     ]
 
   printRedundantCandidates (n+1) "goo" (undefined :: [Int] -> [Int])
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   printRedundantCandidates n "??" (undefined :: [Int] -> [Int] -> [Int])
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   printRedundantCandidates (n+1) "ton" (undefined :: Bool -> Bool)
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "not" not
     ]
 
   printRedundantCandidates n "&|" (undefined :: Bool -> Bool -> Bool)
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "not" not
@@ -115,7 +115,7 @@
   -- through other means
   {-
   printRedundantCandidates n "gcd" (undefined :: Int -> Int -> Int)
-    [ unfun (0::Int)
+    [ con (0::Int)
     , fun "`mod`" (mod :: Int -> Int -> Int)
     ]
   -}
diff --git a/bench/redundants.txt b/bench/redundants.txt
--- a/bench/redundants.txt
+++ b/bench/redundants.txt
@@ -228,32 +228,32 @@
 
 class of 2 equivalent candidates:
 
-    x ? y  =  x + (x + y)
+    x ? y  =  x + dec (dec x)
 
-    x ? y  =  y + (x + x)
+    x ? y  =  dec x + dec x
 
 
-class of 2 equivalent candidates:
+class of 3 equivalent candidates:
 
-    x ? y  =  x + (y + y)
+    x ? y  =  x + dec (dec y)
 
-    x ? y  =  y + (x + y)
+    x ? y  =  y + dec (dec x)
 
+    x ? y  =  dec x + dec y
 
+
 class of 2 equivalent candidates:
 
-    x ? y  =  x + dec (dec x)
+    x ? y  =  x + (x + y)
 
-    x ? y  =  dec x + dec x
+    x ? y  =  y + (x + x)
 
 
-class of 3 equivalent candidates:
-
-    x ? y  =  x + dec (dec y)
+class of 2 equivalent candidates:
 
-    x ? y  =  y + dec (dec x)
+    x ? y  =  x + (y + y)
 
-    x ? y  =  dec x + dec y
+    x ? y  =  y + (x + y)
 
 
 class of 2 equivalent candidates:
@@ -600,55 +600,44 @@
 
 class of 2 equivalent candidates:
 
-    [] ?? xs  =  []
-    (x:xs) ?? []  =  xs
-    (x:xs) ?? (y:ys)  =  xs ?? ys
-
-    [] ?? xs  =  []
-    (x:xs) ?? []  =  xs
-    (x:xs) ?? (y:ys)  =  xs ?? []
-
-
-class of 2 equivalent candidates:
-
-    [] ?? xs  =  []
+    [] ?? xs  =  xs
     (x:xs) ?? []  =  xs
-    (x:xs) ?? (y:ys)  =  ys ?? xs
+    (x:xs) ?? (y:ys)  =  xs ++ ys
 
-    [] ?? xs  =  []
+    [] ?? xs  =  xs
     (x:xs) ?? []  =  xs
-    (x:xs) ?? (y:ys)  =  ys ?? []
+    (x:xs) ?? (y:ys)  =  ys ++ xs
 
 
 class of 2 equivalent candidates:
 
-    [] ?? []  =  []
-    [] ?? (x:xs)  =  xs ?? xs
-    (x:xs) ?? ys  =  xs
+    [] ?? xs  =  xs
+    (x:xs) ?? []  =  []
+    (x:xs) ?? (y:ys)  =  xs ++ ys
 
-    [] ?? []  =  []
-    [] ?? (x:xs)  =  xs ?? []
-    (x:xs) ?? ys  =  xs
+    [] ?? xs  =  xs
+    (x:xs) ?? []  =  []
+    (x:xs) ?? (y:ys)  =  ys ++ xs
 
 
 class of 2 equivalent candidates:
 
-    [] ?? xs  =  xs
+    [] ?? xs  =  []
     (x:xs) ?? []  =  xs
     (x:xs) ?? (y:ys)  =  xs ++ ys
 
-    [] ?? xs  =  xs
+    [] ?? xs  =  []
     (x:xs) ?? []  =  xs
     (x:xs) ?? (y:ys)  =  ys ++ xs
 
 
 class of 2 equivalent candidates:
 
-    [] ?? xs  =  xs
+    [] ?? xs  =  []
     (x:xs) ?? []  =  []
     (x:xs) ?? (y:ys)  =  xs ++ ys
 
-    [] ?? xs  =  xs
+    [] ?? xs  =  []
     (x:xs) ?? []  =  []
     (x:xs) ?? (y:ys)  =  ys ++ xs
 
@@ -657,22 +646,33 @@
 
     [] ?? xs  =  []
     (x:xs) ?? []  =  xs
-    (x:xs) ?? (y:ys)  =  xs ++ ys
+    (x:xs) ?? (y:ys)  =  xs ?? ys
 
     [] ?? xs  =  []
     (x:xs) ?? []  =  xs
-    (x:xs) ?? (y:ys)  =  ys ++ xs
+    (x:xs) ?? (y:ys)  =  xs ?? []
 
 
 class of 2 equivalent candidates:
 
     [] ?? xs  =  []
-    (x:xs) ?? []  =  []
-    (x:xs) ?? (y:ys)  =  xs ++ ys
+    (x:xs) ?? []  =  xs
+    (x:xs) ?? (y:ys)  =  ys ?? xs
 
     [] ?? xs  =  []
-    (x:xs) ?? []  =  []
-    (x:xs) ?? (y:ys)  =  ys ++ xs
+    (x:xs) ?? []  =  xs
+    (x:xs) ?? (y:ys)  =  ys ?? []
+
+
+class of 2 equivalent candidates:
+
+    [] ?? []  =  []
+    [] ?? (x:xs)  =  xs ?? xs
+    (x:xs) ?? ys  =  xs
+
+    [] ?? []  =  []
+    [] ?? (x:xs)  =  xs ?? []
+    (x:xs) ?? ys  =  xs
 
 
 
diff --git a/bench/runtime/lapmatrud/bench/candidates.runtime b/bench/runtime/lapmatrud/bench/candidates.runtime
--- a/bench/runtime/lapmatrud/bench/candidates.runtime
+++ b/bench/runtime/lapmatrud/bench/candidates.runtime
@@ -1,1 +1,1 @@
-10.0
+9.4
diff --git a/bench/runtime/lapmatrud/bench/carry-on.runtime b/bench/runtime/lapmatrud/bench/carry-on.runtime
--- a/bench/runtime/lapmatrud/bench/carry-on.runtime
+++ b/bench/runtime/lapmatrud/bench/carry-on.runtime
@@ -1,1 +1,1 @@
-2.6
+2.4
diff --git a/bench/runtime/lapmatrud/bench/erroneous.runtime b/bench/runtime/lapmatrud/bench/erroneous.runtime
--- a/bench/runtime/lapmatrud/bench/erroneous.runtime
+++ b/bench/runtime/lapmatrud/bench/erroneous.runtime
@@ -1,1 +1,1 @@
-3.1
+2.9
diff --git a/bench/runtime/lapmatrud/bench/gps.runtime b/bench/runtime/lapmatrud/bench/gps.runtime
--- a/bench/runtime/lapmatrud/bench/gps.runtime
+++ b/bench/runtime/lapmatrud/bench/gps.runtime
@@ -1,1 +1,1 @@
-15.8
+14.2
diff --git a/bench/runtime/lapmatrud/bench/gps2.runtime b/bench/runtime/lapmatrud/bench/gps2.runtime
--- a/bench/runtime/lapmatrud/bench/gps2.runtime
+++ b/bench/runtime/lapmatrud/bench/gps2.runtime
@@ -1,1 +1,1 @@
-12.7
+11.7
diff --git a/bench/runtime/lapmatrud/bench/ill-hit.runtime b/bench/runtime/lapmatrud/bench/ill-hit.runtime
--- a/bench/runtime/lapmatrud/bench/ill-hit.runtime
+++ b/bench/runtime/lapmatrud/bench/ill-hit.runtime
@@ -1,1 +1,1 @@
-0.7
+0.5
diff --git a/bench/runtime/lapmatrud/bench/lowtests.runtime b/bench/runtime/lapmatrud/bench/lowtests.runtime
--- a/bench/runtime/lapmatrud/bench/lowtests.runtime
+++ b/bench/runtime/lapmatrud/bench/lowtests.runtime
@@ -1,1 +1,1 @@
-0.5
+0.2
diff --git a/bench/runtime/lapmatrud/bench/p12.runtime b/bench/runtime/lapmatrud/bench/p12.runtime
--- a/bench/runtime/lapmatrud/bench/p12.runtime
+++ b/bench/runtime/lapmatrud/bench/p12.runtime
@@ -1,1 +1,1 @@
-1.7
+1.6
diff --git a/bench/runtime/lapmatrud/bench/redundants.runtime b/bench/runtime/lapmatrud/bench/redundants.runtime
--- a/bench/runtime/lapmatrud/bench/redundants.runtime
+++ b/bench/runtime/lapmatrud/bench/redundants.runtime
@@ -1,1 +1,1 @@
-3.2
+3.1
diff --git a/bench/runtime/lapmatrud/bench/strategies.runtime b/bench/runtime/lapmatrud/bench/strategies.runtime
--- a/bench/runtime/lapmatrud/bench/strategies.runtime
+++ b/bench/runtime/lapmatrud/bench/strategies.runtime
@@ -1,1 +1,1 @@
-6.0
+4.6
diff --git a/bench/runtime/lapmatrud/bench/terpret.runtime b/bench/runtime/lapmatrud/bench/terpret.runtime
--- a/bench/runtime/lapmatrud/bench/terpret.runtime
+++ b/bench/runtime/lapmatrud/bench/terpret.runtime
@@ -1,1 +1,1 @@
-7.7
+10.2
diff --git a/bench/runtime/lapmatrud/bench/unique.runtime b/bench/runtime/lapmatrud/bench/unique.runtime
--- a/bench/runtime/lapmatrud/bench/unique.runtime
+++ b/bench/runtime/lapmatrud/bench/unique.runtime
@@ -1,1 +1,1 @@
-2.5
+2.4
diff --git a/bench/runtime/lapmatrud/bench/weird.runtime b/bench/runtime/lapmatrud/bench/weird.runtime
--- a/bench/runtime/lapmatrud/bench/weird.runtime
+++ b/bench/runtime/lapmatrud/bench/weird.runtime
@@ -1,1 +1,1 @@
-2.6
+3.3
diff --git a/bench/runtime/lapmatrud/eg/bits.runtime b/bench/runtime/lapmatrud/eg/bits.runtime
--- a/bench/runtime/lapmatrud/eg/bits.runtime
+++ b/bench/runtime/lapmatrud/eg/bits.runtime
@@ -1,1 +1,1 @@
-3.2
+3.1
diff --git a/bench/runtime/lapmatrud/eg/bools.runtime b/bench/runtime/lapmatrud/eg/bools.runtime
--- a/bench/runtime/lapmatrud/eg/bools.runtime
+++ b/bench/runtime/lapmatrud/eg/bools.runtime
@@ -1,1 +1,1 @@
-1.9
+1.6
diff --git a/bench/runtime/lapmatrud/eg/bst.runtime b/bench/runtime/lapmatrud/eg/bst.runtime
--- a/bench/runtime/lapmatrud/eg/bst.runtime
+++ b/bench/runtime/lapmatrud/eg/bst.runtime
@@ -1,1 +1,1 @@
-4.8
+4.1
diff --git a/bench/runtime/lapmatrud/eg/conditionals.runtime b/bench/runtime/lapmatrud/eg/conditionals.runtime
new file mode 100644
--- /dev/null
+++ b/bench/runtime/lapmatrud/eg/conditionals.runtime
@@ -0,0 +1,1 @@
+8.7
diff --git a/bench/runtime/lapmatrud/eg/count.runtime b/bench/runtime/lapmatrud/eg/count.runtime
--- a/bench/runtime/lapmatrud/eg/count.runtime
+++ b/bench/runtime/lapmatrud/eg/count.runtime
@@ -1,1 +1,1 @@
-0.8
+0.5
diff --git a/bench/runtime/lapmatrud/eg/digits.runtime b/bench/runtime/lapmatrud/eg/digits.runtime
new file mode 100644
--- /dev/null
+++ b/bench/runtime/lapmatrud/eg/digits.runtime
@@ -0,0 +1,1 @@
+5.5
diff --git a/bench/runtime/lapmatrud/eg/dupos.runtime b/bench/runtime/lapmatrud/eg/dupos.runtime
--- a/bench/runtime/lapmatrud/eg/dupos.runtime
+++ b/bench/runtime/lapmatrud/eg/dupos.runtime
@@ -1,1 +1,1 @@
-2.2
+1.1
diff --git a/bench/runtime/lapmatrud/eg/factorial.runtime b/bench/runtime/lapmatrud/eg/factorial.runtime
--- a/bench/runtime/lapmatrud/eg/factorial.runtime
+++ b/bench/runtime/lapmatrud/eg/factorial.runtime
@@ -1,1 +1,1 @@
-1.6
+1.4
diff --git a/bench/runtime/lapmatrud/eg/fib01.runtime b/bench/runtime/lapmatrud/eg/fib01.runtime
--- a/bench/runtime/lapmatrud/eg/fib01.runtime
+++ b/bench/runtime/lapmatrud/eg/fib01.runtime
@@ -1,1 +1,1 @@
-0.6
+0.5
diff --git a/bench/runtime/lapmatrud/eg/fibonacci.runtime b/bench/runtime/lapmatrud/eg/fibonacci.runtime
--- a/bench/runtime/lapmatrud/eg/fibonacci.runtime
+++ b/bench/runtime/lapmatrud/eg/fibonacci.runtime
@@ -1,1 +1,1 @@
-3.5
+3.2
diff --git a/bench/runtime/lapmatrud/eg/gcd.runtime b/bench/runtime/lapmatrud/eg/gcd.runtime
--- a/bench/runtime/lapmatrud/eg/gcd.runtime
+++ b/bench/runtime/lapmatrud/eg/gcd.runtime
@@ -1,1 +1,1 @@
-0.2
+0.1
diff --git a/bench/runtime/lapmatrud/eg/higher.runtime b/bench/runtime/lapmatrud/eg/higher.runtime
--- a/bench/runtime/lapmatrud/eg/higher.runtime
+++ b/bench/runtime/lapmatrud/eg/higher.runtime
@@ -1,1 +1,1 @@
-1.4
+0.9
diff --git a/bench/runtime/lapmatrud/eg/ints.runtime b/bench/runtime/lapmatrud/eg/ints.runtime
--- a/bench/runtime/lapmatrud/eg/ints.runtime
+++ b/bench/runtime/lapmatrud/eg/ints.runtime
@@ -1,1 +1,1 @@
-1.2
+0.9
diff --git a/bench/runtime/lapmatrud/eg/list.runtime b/bench/runtime/lapmatrud/eg/list.runtime
--- a/bench/runtime/lapmatrud/eg/list.runtime
+++ b/bench/runtime/lapmatrud/eg/list.runtime
@@ -1,1 +1,1 @@
-0.6
+0.8
diff --git a/bench/runtime/lapmatrud/eg/oddeven.runtime b/bench/runtime/lapmatrud/eg/oddeven.runtime
--- a/bench/runtime/lapmatrud/eg/oddeven.runtime
+++ b/bench/runtime/lapmatrud/eg/oddeven.runtime
@@ -1,1 +1,1 @@
-1.6
+1.7
diff --git a/bench/runtime/lapmatrud/eg/pow.runtime b/bench/runtime/lapmatrud/eg/pow.runtime
--- a/bench/runtime/lapmatrud/eg/pow.runtime
+++ b/bench/runtime/lapmatrud/eg/pow.runtime
@@ -1,1 +1,1 @@
-3.0
+1.6
diff --git a/bench/runtime/lapmatrud/eg/setelem.runtime b/bench/runtime/lapmatrud/eg/setelem.runtime
--- a/bench/runtime/lapmatrud/eg/setelem.runtime
+++ b/bench/runtime/lapmatrud/eg/setelem.runtime
@@ -1,1 +1,1 @@
-0.8
+1.0
diff --git a/bench/runtime/lapmatrud/eg/sort.runtime b/bench/runtime/lapmatrud/eg/sort.runtime
--- a/bench/runtime/lapmatrud/eg/sort.runtime
+++ b/bench/runtime/lapmatrud/eg/sort.runtime
@@ -1,1 +1,1 @@
-3.4
+1.8
diff --git a/bench/runtime/lapmatrud/eg/subset.runtime b/bench/runtime/lapmatrud/eg/subset.runtime
--- a/bench/runtime/lapmatrud/eg/subset.runtime
+++ b/bench/runtime/lapmatrud/eg/subset.runtime
@@ -1,1 +1,1 @@
-0.6
+0.5
diff --git a/bench/runtime/lapmatrud/eg/these.runtime b/bench/runtime/lapmatrud/eg/these.runtime
--- a/bench/runtime/lapmatrud/eg/these.runtime
+++ b/bench/runtime/lapmatrud/eg/these.runtime
@@ -1,1 +1,1 @@
-1.9
+1.1
diff --git a/bench/runtime/lapmatrud/eg/tri.runtime b/bench/runtime/lapmatrud/eg/tri.runtime
--- a/bench/runtime/lapmatrud/eg/tri.runtime
+++ b/bench/runtime/lapmatrud/eg/tri.runtime
@@ -1,1 +1,1 @@
-0.3
+0.2
diff --git a/bench/runtime/lapmatrud/eg/tuple.runtime b/bench/runtime/lapmatrud/eg/tuple.runtime
--- a/bench/runtime/lapmatrud/eg/tuple.runtime
+++ b/bench/runtime/lapmatrud/eg/tuple.runtime
@@ -1,1 +1,1 @@
-0.8
+0.7
diff --git a/bench/runtime/zero/bench/candidates.runtime b/bench/runtime/zero/bench/candidates.runtime
--- a/bench/runtime/zero/bench/candidates.runtime
+++ b/bench/runtime/zero/bench/candidates.runtime
@@ -1,1 +1,1 @@
-17.4
+18.5
diff --git a/bench/runtime/zero/bench/carry-on.runtime b/bench/runtime/zero/bench/carry-on.runtime
--- a/bench/runtime/zero/bench/carry-on.runtime
+++ b/bench/runtime/zero/bench/carry-on.runtime
@@ -1,1 +1,1 @@
-4.8
+5.4
diff --git a/bench/runtime/zero/bench/erroneous.runtime b/bench/runtime/zero/bench/erroneous.runtime
--- a/bench/runtime/zero/bench/erroneous.runtime
+++ b/bench/runtime/zero/bench/erroneous.runtime
@@ -1,1 +1,1 @@
-5.6
+6.9
diff --git a/bench/runtime/zero/bench/gps.runtime b/bench/runtime/zero/bench/gps.runtime
--- a/bench/runtime/zero/bench/gps.runtime
+++ b/bench/runtime/zero/bench/gps.runtime
@@ -1,1 +1,1 @@
-27.9
+34.3
diff --git a/bench/runtime/zero/bench/gps2.runtime b/bench/runtime/zero/bench/gps2.runtime
--- a/bench/runtime/zero/bench/gps2.runtime
+++ b/bench/runtime/zero/bench/gps2.runtime
@@ -1,1 +1,1 @@
-22.8
+24.9
diff --git a/bench/runtime/zero/bench/ill-hit.runtime b/bench/runtime/zero/bench/ill-hit.runtime
--- a/bench/runtime/zero/bench/ill-hit.runtime
+++ b/bench/runtime/zero/bench/ill-hit.runtime
@@ -1,1 +1,1 @@
-1.1
+1.2
diff --git a/bench/runtime/zero/bench/lowtests.runtime b/bench/runtime/zero/bench/lowtests.runtime
--- a/bench/runtime/zero/bench/lowtests.runtime
+++ b/bench/runtime/zero/bench/lowtests.runtime
@@ -1,1 +1,1 @@
-0.8
+0.6
diff --git a/bench/runtime/zero/bench/p12.runtime b/bench/runtime/zero/bench/p12.runtime
--- a/bench/runtime/zero/bench/p12.runtime
+++ b/bench/runtime/zero/bench/p12.runtime
@@ -1,1 +1,1 @@
-3.0
+3.5
diff --git a/bench/runtime/zero/bench/redundants.runtime b/bench/runtime/zero/bench/redundants.runtime
--- a/bench/runtime/zero/bench/redundants.runtime
+++ b/bench/runtime/zero/bench/redundants.runtime
@@ -1,1 +1,1 @@
-6.2
+8.1
diff --git a/bench/runtime/zero/bench/strategies.runtime b/bench/runtime/zero/bench/strategies.runtime
--- a/bench/runtime/zero/bench/strategies.runtime
+++ b/bench/runtime/zero/bench/strategies.runtime
@@ -1,1 +1,1 @@
-9.1
+10.7
diff --git a/bench/runtime/zero/bench/terpret.runtime b/bench/runtime/zero/bench/terpret.runtime
--- a/bench/runtime/zero/bench/terpret.runtime
+++ b/bench/runtime/zero/bench/terpret.runtime
@@ -1,1 +1,1 @@
-14.2
+22.8
diff --git a/bench/runtime/zero/bench/unique.runtime b/bench/runtime/zero/bench/unique.runtime
--- a/bench/runtime/zero/bench/unique.runtime
+++ b/bench/runtime/zero/bench/unique.runtime
@@ -1,1 +1,1 @@
-4.8
+5.3
diff --git a/bench/runtime/zero/bench/weird.runtime b/bench/runtime/zero/bench/weird.runtime
--- a/bench/runtime/zero/bench/weird.runtime
+++ b/bench/runtime/zero/bench/weird.runtime
@@ -1,1 +1,1 @@
-4.7
+7.3
diff --git a/bench/runtime/zero/eg/arith.runtime b/bench/runtime/zero/eg/arith.runtime
--- a/bench/runtime/zero/eg/arith.runtime
+++ b/bench/runtime/zero/eg/arith.runtime
@@ -1,1 +1,1 @@
-1.9
+2.4
diff --git a/bench/runtime/zero/eg/bits.runtime b/bench/runtime/zero/eg/bits.runtime
--- a/bench/runtime/zero/eg/bits.runtime
+++ b/bench/runtime/zero/eg/bits.runtime
@@ -1,1 +1,1 @@
-5.8
+6.1
diff --git a/bench/runtime/zero/eg/bools.runtime b/bench/runtime/zero/eg/bools.runtime
--- a/bench/runtime/zero/eg/bools.runtime
+++ b/bench/runtime/zero/eg/bools.runtime
@@ -1,1 +1,1 @@
-3.2
+3.4
diff --git a/bench/runtime/zero/eg/conditionals.runtime b/bench/runtime/zero/eg/conditionals.runtime
new file mode 100644
--- /dev/null
+++ b/bench/runtime/zero/eg/conditionals.runtime
@@ -0,0 +1,1 @@
+16.4
diff --git a/bench/runtime/zero/eg/count.runtime b/bench/runtime/zero/eg/count.runtime
--- a/bench/runtime/zero/eg/count.runtime
+++ b/bench/runtime/zero/eg/count.runtime
@@ -1,1 +1,1 @@
-1.1
+1.2
diff --git a/bench/runtime/zero/eg/digits.runtime b/bench/runtime/zero/eg/digits.runtime
new file mode 100644
--- /dev/null
+++ b/bench/runtime/zero/eg/digits.runtime
@@ -0,0 +1,1 @@
+10.9
diff --git a/bench/runtime/zero/eg/dupos.runtime b/bench/runtime/zero/eg/dupos.runtime
--- a/bench/runtime/zero/eg/dupos.runtime
+++ b/bench/runtime/zero/eg/dupos.runtime
@@ -1,1 +1,1 @@
-3.7
+2.5
diff --git a/bench/runtime/zero/eg/either.runtime b/bench/runtime/zero/eg/either.runtime
--- a/bench/runtime/zero/eg/either.runtime
+++ b/bench/runtime/zero/eg/either.runtime
@@ -1,1 +1,1 @@
-0.3
+0.4
diff --git a/bench/runtime/zero/eg/factorial.runtime b/bench/runtime/zero/eg/factorial.runtime
--- a/bench/runtime/zero/eg/factorial.runtime
+++ b/bench/runtime/zero/eg/factorial.runtime
@@ -1,1 +1,1 @@
-2.5
+2.8
diff --git a/bench/runtime/zero/eg/fib01.runtime b/bench/runtime/zero/eg/fib01.runtime
--- a/bench/runtime/zero/eg/fib01.runtime
+++ b/bench/runtime/zero/eg/fib01.runtime
@@ -1,1 +1,1 @@
-1.1
+1.2
diff --git a/bench/runtime/zero/eg/fibonacci.runtime b/bench/runtime/zero/eg/fibonacci.runtime
--- a/bench/runtime/zero/eg/fibonacci.runtime
+++ b/bench/runtime/zero/eg/fibonacci.runtime
@@ -1,1 +1,1 @@
-6.2
+6.9
diff --git a/bench/runtime/zero/eg/higher.runtime b/bench/runtime/zero/eg/higher.runtime
--- a/bench/runtime/zero/eg/higher.runtime
+++ b/bench/runtime/zero/eg/higher.runtime
@@ -1,1 +1,1 @@
-1.8
+2.0
diff --git a/bench/runtime/zero/eg/ints.runtime b/bench/runtime/zero/eg/ints.runtime
--- a/bench/runtime/zero/eg/ints.runtime
+++ b/bench/runtime/zero/eg/ints.runtime
@@ -1,1 +1,1 @@
-1.9
+2.2
diff --git a/bench/runtime/zero/eg/list.runtime b/bench/runtime/zero/eg/list.runtime
--- a/bench/runtime/zero/eg/list.runtime
+++ b/bench/runtime/zero/eg/list.runtime
@@ -1,1 +1,1 @@
-1.6
+1.8
diff --git a/bench/runtime/zero/eg/oddeven.runtime b/bench/runtime/zero/eg/oddeven.runtime
--- a/bench/runtime/zero/eg/oddeven.runtime
+++ b/bench/runtime/zero/eg/oddeven.runtime
@@ -1,1 +1,1 @@
-3.0
+3.7
diff --git a/bench/runtime/zero/eg/pow.runtime b/bench/runtime/zero/eg/pow.runtime
--- a/bench/runtime/zero/eg/pow.runtime
+++ b/bench/runtime/zero/eg/pow.runtime
@@ -1,1 +1,1 @@
-5.2
+3.6
diff --git a/bench/runtime/zero/eg/replicate.runtime b/bench/runtime/zero/eg/replicate.runtime
--- a/bench/runtime/zero/eg/replicate.runtime
+++ b/bench/runtime/zero/eg/replicate.runtime
@@ -1,1 +1,1 @@
-0.4
+0.5
diff --git a/bench/runtime/zero/eg/setelem.runtime b/bench/runtime/zero/eg/setelem.runtime
--- a/bench/runtime/zero/eg/setelem.runtime
+++ b/bench/runtime/zero/eg/setelem.runtime
@@ -1,1 +1,1 @@
-1.9
+2.1
diff --git a/bench/runtime/zero/eg/sort.runtime b/bench/runtime/zero/eg/sort.runtime
--- a/bench/runtime/zero/eg/sort.runtime
+++ b/bench/runtime/zero/eg/sort.runtime
@@ -1,1 +1,1 @@
-6.0
+3.9
diff --git a/bench/runtime/zero/eg/spec.runtime b/bench/runtime/zero/eg/spec.runtime
--- a/bench/runtime/zero/eg/spec.runtime
+++ b/bench/runtime/zero/eg/spec.runtime
@@ -1,1 +1,1 @@
-1.5
+1.9
diff --git a/bench/runtime/zero/eg/take-drop.runtime b/bench/runtime/zero/eg/take-drop.runtime
--- a/bench/runtime/zero/eg/take-drop.runtime
+++ b/bench/runtime/zero/eg/take-drop.runtime
@@ -1,1 +1,1 @@
-0.6
+0.7
diff --git a/bench/runtime/zero/eg/tapps.runtime b/bench/runtime/zero/eg/tapps.runtime
--- a/bench/runtime/zero/eg/tapps.runtime
+++ b/bench/runtime/zero/eg/tapps.runtime
@@ -1,1 +1,1 @@
-0.8
+1.0
diff --git a/bench/runtime/zero/eg/these.runtime b/bench/runtime/zero/eg/these.runtime
--- a/bench/runtime/zero/eg/these.runtime
+++ b/bench/runtime/zero/eg/these.runtime
@@ -1,1 +1,1 @@
-3.4
+2.3
diff --git a/bench/runtime/zero/eg/tree.runtime b/bench/runtime/zero/eg/tree.runtime
--- a/bench/runtime/zero/eg/tree.runtime
+++ b/bench/runtime/zero/eg/tree.runtime
@@ -1,1 +1,1 @@
-2.6
+3.2
diff --git a/bench/runtime/zero/proto/u-conjure.runtime b/bench/runtime/zero/proto/u-conjure.runtime
--- a/bench/runtime/zero/proto/u-conjure.runtime
+++ b/bench/runtime/zero/proto/u-conjure.runtime
@@ -1,1 +1,1 @@
-0.4
+0.5
diff --git a/bench/self.hs b/bench/self.hs
--- a/bench/self.hs
+++ b/bench/self.hs
@@ -13,8 +13,8 @@
 
 ingredients :: [Ingredient]
 ingredients =
-  [ unfun (0::Int)
-  , unfun (1::Int)
+  [ con (0::Int)
+  , con (1::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
   , maxSize 3
diff --git a/bench/self.txt b/bench/self.txt
--- a/bench/self.txt
+++ b/bench/self.txt
@@ -2,35 +2,35 @@
 -- testing 360 combinations of argument values
 -- pruning with 0/0 rules
 -- 4 candidates of size 1
--- 6 candidates of size 2
--- 26 candidates of size 3
--- tested 12 candidates
+-- 0 candidates of size 2
+-- 24 candidates of size 3
+-- tested 6 candidates
 x ? y  =  x + y
 
 (?) :: Int -> Int -> Int
 -- testing 360 combinations of argument values
 -- pruning with 0/0 rules
 -- 4 candidates of size 1
--- 4 candidates of size 2
--- 31 candidates of size 3
--- tested 22 candidates
+-- 0 candidates of size 2
+-- 24 candidates of size 3
+-- tested 18 candidates
 x ? y  =  x * y
 
 i :: Int -> Int
 -- testing 360 combinations of argument values
 -- pruning with 0/0 rules
 -- 3 candidates of size 1
--- 2 candidates of size 2
--- 13 candidates of size 3
--- tested 8 candidates
+-- 0 candidates of size 2
+-- 10 candidates of size 3
+-- tested 6 candidates
 i x  =  x + 1
 
 d :: Int -> Int
 -- testing 360 combinations of argument values
 -- pruning with 0/0 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 12 candidates of size 3
--- tested 18 candidates
+-- 0 candidates of size 2
+-- 10 candidates of size 3
+-- tested 13 candidates
 d  =  undefined  -- search exhausted
 
diff --git a/bench/strategies.hs b/bench/strategies.hs
--- a/bench/strategies.hs
+++ b/bench/strategies.hs
@@ -27,10 +27,10 @@
     "default"           -> [1,1,1,0]
     "without reasoning" -> [0,1,1,0]
     "without descent"   -> [1,0,1,0]
-    "without ad-hoc"    -> [1,1,0,0]
+    "without assorted"  -> [1,1,0,0]
     "only reasoning"    -> [1,0,0,0]
     "only descent"      -> [0,1,0,0]
-    "only ad-hoc"       -> [0,0,1,0]
+    "only assorted"     -> [0,0,1,0]
     "only typed"        -> [0,0,0,0]
     _                   -> error "unknown strategy"
 
@@ -45,10 +45,10 @@
   , "default"
   , "without reasoning"
   , "without descent"
-  , "without ad-hoc"
+  , "without assorted"
   , "only reasoning"
   , "only descent"
-  , "only ad-hoc"
+  , "only assorted"
   , "only typed"
   ]
 
@@ -61,8 +61,8 @@
 
 ingredients :: [Ingredient]
 ingredients = 
-    [ unfun (0::Int)
-    , unfun (1::Int)
+    [ con (0::Int)
+    , con (1::Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
diff --git a/bench/strategies.txt b/bench/strategies.txt
--- a/bench/strategies.txt
+++ b/bench/strategies.txt
@@ -3,13 +3,13 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 7 candidates of size 3
--- 8 candidates of size 4
--- 23 candidates of size 5
--- 30 candidates of size 6
--- 82 candidates of size 7
--- tested 84 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 18 candidates of size 5
+-- 0 candidates of size 6
+-- 67 candidates of size 7
+-- tested 88 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
@@ -18,13 +18,13 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 7 candidates of size 3
--- 8 candidates of size 4
--- 28 candidates of size 5
--- 35 candidates of size 6
--- 167 candidates of size 7
--- tested 95 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 23 candidates of size 5
+-- 0 candidates of size 6
+-- 147 candidates of size 7
+-- tested 173 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
@@ -33,13 +33,13 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 16 candidates of size 3
--- 17 candidates of size 4
--- 279 candidates of size 5
--- 313 candidates of size 6
--- 5763 candidates of size 7
--- tested 656 candidates
+-- 0 candidates of size 2
+-- 15 candidates of size 3
+-- 0 candidates of size 4
+-- 270 candidates of size 5
+-- 0 candidates of size 6
+-- 5572 candidates of size 7
+-- tested 5848 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
@@ -48,28 +48,28 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 7 candidates of size 3
--- 8 candidates of size 4
--- 28 candidates of size 5
--- 35 candidates of size 6
--- 252 candidates of size 7
--- tested 148 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 23 candidates of size 5
+-- 0 candidates of size 6
+-- 232 candidates of size 7
+-- tested 226 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
--- strategy: without ad-hoc
+-- strategy: without assorted
 factorial :: Int -> Int
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 6 candidates of size 2
--- 9 candidates of size 3
--- 18 candidates of size 4
--- 31 candidates of size 5
--- 59 candidates of size 6
--- 171 candidates of size 7
--- tested 137 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 25 candidates of size 5
+-- 1 candidates of size 6
+-- 148 candidates of size 7
+-- tested 176 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
@@ -78,13 +78,13 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 6 candidates of size 2
--- 9 candidates of size 3
--- 18 candidates of size 4
--- 41 candidates of size 5
--- 64 candidates of size 6
--- 307 candidates of size 7
--- tested 251 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 35 candidates of size 5
+-- 6 candidates of size 6
+-- 284 candidates of size 7
+-- tested 244 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
@@ -93,28 +93,28 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 6 candidates of size 2
--- 18 candidates of size 3
--- 36 candidates of size 4
--- 287 candidates of size 5
--- 571 candidates of size 6
--- 5843 candidates of size 7
--- tested 946 candidates
+-- 0 candidates of size 2
+-- 15 candidates of size 3
+-- 0 candidates of size 4
+-- 272 candidates of size 5
+-- 1 candidates of size 6
+-- 5573 candidates of size 7
+-- tested 5851 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
--- strategy: only ad-hoc
+-- strategy: only assorted
 factorial :: Int -> Int
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 16 candidates of size 3
--- 17 candidates of size 4
--- 279 candidates of size 5
--- 313 candidates of size 6
--- 6281 candidates of size 7
--- tested 1004 candidates
+-- 0 candidates of size 2
+-- 15 candidates of size 3
+-- 0 candidates of size 4
+-- 270 candidates of size 5
+-- 0 candidates of size 6
+-- 6090 candidates of size 7
+-- tested 6196 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
@@ -123,13 +123,13 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 6 candidates of size 2
--- 18 candidates of size 3
--- 36 candidates of size 4
--- 315 candidates of size 5
--- 585 candidates of size 6
--- 6915 candidates of size 7
--- tested 1876 candidates
+-- 0 candidates of size 2
+-- 15 candidates of size 3
+-- 0 candidates of size 4
+-- 300 candidates of size 5
+-- 15 candidates of size 6
+-- 6645 candidates of size 7
+-- tested 6241 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
diff --git a/bench/terpret.hs b/bench/terpret.hs
--- a/bench/terpret.hs
+++ b/bench/terpret.hs
@@ -33,15 +33,15 @@
 -- the same ingredients are used for TerpreT #1, #2 and #3
 ingredients123 :: [Ingredient]
 ingredients123  =
-  [ unfun False
-  , unfun True
+  [ con False
+  , con True
   , fun "not" not
   , fun "&&" (&&)
   , fun "||" (||)
-  , unfun ([] :: [Bool])
+  , con ([] :: [Bool])
   , fun ":" ((:) :: Bool -> [Bool] -> [Bool])
 --, fun "map" (map :: (Bool -> Bool) -> [Bool] -> [Bool])
-  , iif (undefined :: [Bool])
+  , guard
   ]
 
 
@@ -110,13 +110,13 @@
 
   conjure "cshift" t4p1 $ ingredients123 ++
     [ fun ",," ((,,) :: Bool -> Bool -> Bool -> (Bool,Bool,Bool))
-    , iif (undefined :: (Bool,Bool,Bool))
+    , guard
     , target 50400
     ]
 
   conjure "cshift" t4p2 $ ingredients123 ++
     [ fun ",," ((,,) :: Bool -> Bool -> Bool -> (Bool,Bool,Bool))
-    , iif (undefined :: (Bool,Bool,Bool))
+    , guard
     ]
 
 
@@ -136,15 +136,12 @@
 t5c  =  do
   putStrLn "TerpreT benchmark #5: full adder\n"
 
-  -- using ingredients123 below works, but increases the runtime to 18 seconds
-  -- let's leave it commented out so runtime is faster when running automated tests
-  -- BENCHMARK: uncomment ingredients123
-  conjure "fadder" t5p $ -- ingredients123 ++
+  conjure "fadder" t5p $ ingredients123 ++
     [ fun "not" not
     , fun "," ((,) :: Bool -> Bool -> (Bool,Bool))
     , fun "==" ((==) :: Bool -> Bool -> Bool)
 --  , fun "^^" ((/=) :: Bool -> Bool -> Bool) -- poor man's xor
-    , iif (undefined :: (Bool,Bool))
+    , guard
     ]
 -- the printed function is weird, but correct
 -- fadder p q r  =  if p == q then (p,r) else (r,not r)
@@ -165,7 +162,7 @@
     [ fun ",," ((,,) :: Bool -> Bool -> Bool -> (Bool,Bool,Bool))
     , fun "==" ((==) :: Bool -> Bool -> Bool)
     , fun "^^" ((/=) :: Bool -> Bool -> Bool) -- poor man's xor
-    , iif (undefined :: (Bool,Bool,Bool))
+    , guard
     , maxSize 6
     ]
 
@@ -192,9 +189,9 @@
     ]
 
   conjure "`access`" t7p
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , unfun ([] :: [A])
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , con ([] :: [A])
     , fun ":" ((:) :: A -> [A] -> [A])
     , fun "-" ((-) :: Int -> Int -> Int)
     , fun "undefined" (undefined :: A)
@@ -212,8 +209,8 @@
   putStrLn "TerpreT benchmark #8: decrement elements\n"
 
   conjure "decrelements" t8p
-    [ unfun (1 :: Int)
-    , unfun ([] :: [Int])
+    [ con (1 :: Int)
+    , con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "-" ((-) :: Int -> Int -> Int)
     , fun "map" (map :: (Int -> Int) -> [Int] -> [Int])
@@ -222,8 +219,8 @@
   -- introduce lambdas
 
   conjure "decrelements" t8p
-    [ unfun (1 :: Int)
-    , unfun ([] :: [Int])
+    [ con (1 :: Int)
+    , con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "-" ((-) :: Int -> Int -> Int)
     , fun "map" (map :: (Int -> Int) -> [Int] -> [Int])
diff --git a/bench/terpret.txt b/bench/terpret.txt
--- a/bench/terpret.txt
+++ b/bench/terpret.txt
@@ -7,9 +7,9 @@
 -- 0 candidates of size 2
 -- 4 candidates of size 3
 -- 0 candidates of size 4
--- 11 candidates of size 5
--- 5 candidates of size 6
--- tested 18 candidates
+-- 8 candidates of size 5
+-- 1 candidates of size 6
+-- tested 15 candidates
 invert []  =  []
 invert (p:ps)  =  not p:invert ps
 
@@ -33,40 +33,43 @@
 -- 0 candidates of size 2
 -- 4 candidates of size 3
 -- 0 candidates of size 4
--- 11 candidates of size 5
--- 5 candidates of size 6
--- 31 candidates of size 7
--- 52 candidates of size 8
--- 128 candidates of size 9
--- tested 154 candidates
+-- 8 candidates of size 5
+-- 1 candidates of size 6
+-- 16 candidates of size 7
+-- 4 candidates of size 8
+-- 35 candidates of size 9
+-- 15 candidates of size 10
+-- tested 71 candidates
 decrement []  =  []
-decrement (p:ps)  =  not p:(if p then ps else decrement ps)
+decrement (p:ps)
+  | p  =  False:ps
+  | otherwise  =  True:decrement ps
 
 TerpreT benchmark #4: controlled shift
 
 cshift :: (Bool,Bool,Bool) -> (Bool,Bool,Bool)
 -- testing 4 combinations of argument values
--- pruning with 41/51 rules
+-- pruning with 37/47 rules
 -- reasoning produced 2 incorrect properties, please re-run with more tests for faster results
 -- 1 candidates of size 1
 -- 0 candidates of size 2
 -- 0 candidates of size 3
--- 10 candidates of size 4
--- 0 candidates of size 5
--- 0 candidates of size 6
--- 40 candidates of size 7
--- 0 candidates of size 8
--- 0 candidates of size 9
--- 360 candidates of size 10
--- 4 candidates of size 11
--- tested 412 candidates
-cshift (p,q,r)  =  if p
-                   then (p,r,q)
-                   else (p,q,r)
+-- 12 candidates of size 4
+-- 125 candidates of size 5
+-- 225 candidates of size 6
+-- 665 candidates of size 7
+-- 1242 candidates of size 8
+-- 3087 candidates of size 9
+-- 9281 candidates of size 10
+-- 180325 candidates of size 11
+-- tested 40096 candidates
+cshift (p,q,r)
+  | p  =  (p,r,q)
+  | otherwise  =  (p,q,r)
 
 cshift :: Bool -> Bool -> Bool -> (Bool,Bool,Bool)
 -- testing 4 combinations of argument values
--- pruning with 41/51 rules
+-- pruning with 37/47 rules
 -- reasoning produced 2 incorrect properties, please re-run with more tests for faster results
 -- 0 candidates of size 1
 -- 0 candidates of size 2
@@ -84,16 +87,16 @@
 
 fadder :: Bool -> Bool -> Bool -> (Bool,Bool)
 -- testing 8 combinations of argument values
--- pruning with 18/22 rules
+-- pruning with 72/90 rules
 -- 0 candidates of size 1
 -- 0 candidates of size 2
--- 9 candidates of size 3
--- 18 candidates of size 4
--- 27 candidates of size 5
--- 36 candidates of size 6
--- 45 candidates of size 7
--- 271 candidates of size 8
--- tested 406 candidates
+-- 25 candidates of size 3
+-- 60 candidates of size 4
+-- 126 candidates of size 5
+-- 348 candidates of size 6
+-- 999 candidates of size 7
+-- 7009 candidates of size 8
+-- tested 8567 candidates
 fadder False False False  =  (False,False)
 fadder False False True  =  (False,True)
 fadder False True False  =  (False,True)
@@ -107,15 +110,15 @@
 
 adder2 :: (Bool,Bool) -> (Bool,Bool) -> (Bool,Bool,Bool)
 -- testing 5 combinations of argument values
--- pruning with 74/92 rules
+-- pruning with 70/88 rules
 -- reasoning produced 2 incorrect properties, please re-run with more tests for faster results
 -- 0 candidates of size 1
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 8 candidates of size 4
--- 0 candidates of size 5
--- 0 candidates of size 6
--- tested 8 candidates
+-- 128 candidates of size 5
+-- 408 candidates of size 6
+-- tested 544 candidates
 adder2  =  undefined  -- search exhausted
 
 TerpreT benchmark #7: access
@@ -153,10 +156,10 @@
 -- 0 candidates of size 2
 -- 2 candidates of size 3
 -- 1 candidates of size 4
--- 6 candidates of size 5
+-- 4 candidates of size 5
 -- 6 candidates of size 6
--- 19 candidates of size 7
--- tested 19 candidates
+-- 10 candidates of size 7
+-- tested 25 candidates
 decrelements []  =  []
 decrelements (x:xs)  =  x - 1:decrelements xs
 
diff --git a/bench/unique.hs b/bench/unique.hs
--- a/bench/unique.hs
+++ b/bench/unique.hs
@@ -64,43 +64,43 @@
   let n = 5
 
   printUniqueCandidates (n+2) "foo" (undefined :: Int -> Int)
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
 
   printUniqueCandidates n "?" (undefined :: Int -> Int -> Int)
-    [ unfun (0 :: Int)
+    [ con (0 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "dec" (subtract 1 :: Int -> Int)
     ]
 
   printUniqueCandidates (n+2) "goo" (undefined :: [Int] -> [Int])
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   printUniqueCandidates n "??" (undefined :: [Int] -> [Int] -> [Int])
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   printUniqueCandidates (n+2) "ton" (undefined :: Bool -> Bool)
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "not" not
     ]
 
   printUniqueCandidates n "&|" (undefined :: Bool -> Bool -> Bool)
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "not" not
diff --git a/bench/unique.txt b/bench/unique.txt
--- a/bench/unique.txt
+++ b/bench/unique.txt
@@ -142,8 +142,6 @@
 foo 1  =  1
 foo x  =  0
 
-foo x  =  x * x - 1
-
 foo x  =  x + (x + x)
 
 foo x  =  x + (x + 1)
@@ -178,6 +176,8 @@
 
 foo x  =  1 - x * x
 
+foo x  =  x * x - 1
+
 foo 1  =  0
 foo x  =  x + x
 
@@ -206,9 +206,6 @@
 foo x  =  1 - x
 
 foo 0  =  0
-foo x  =  x * x - 1
-
-foo 0  =  0
 foo x  =  x + (x + 1)
 
 foo 0  =  0
@@ -235,7 +232,7 @@
 foo 0  =  0
 foo x  =  1 - x * x
 
-foo 0  =  1
+foo 0  =  0
 foo x  =  x * x - 1
 
 foo 0  =  1
@@ -277,6 +274,9 @@
 foo 0  =  1
 foo x  =  0 - (x + 1)
 
+foo 0  =  1
+foo x  =  x * x - 1
+
 foo 0  =  0
 foo 1  =  0
 foo x  =  x + 1
@@ -317,63 +317,6 @@
 foo 1  =  1
 foo x  =  0 - x
 
-foo 0  =  0
-foo x  =  x + foo (x - 1)
-
-foo 0  =  0
-foo x  =  foo (x - 1) + 1
-
-foo 0  =  0
-foo x  =  x * foo (x - 1)
-
-foo 0  =  0
-foo x  =  x - foo (x - 1)
-
-foo 0  =  0
-foo x  =  foo (x - 1) - x
-
-foo 0  =  0
-foo x  =  foo (x - 1) - 1
-
-foo 0  =  0
-foo x  =  1 - foo (x - 1)
-
-foo 0  =  1
-foo x  =  x + foo (x - 1)
-
-foo 0  =  1
-foo x  =  foo (x - 1) + 1
-
-foo 0  =  1
-foo x  =  x * foo (x - 1)
-
-foo 0  =  1
-foo x  =  x - foo (x - 1)
-
-foo 0  =  1
-foo x  =  foo (x - 1) - x
-
-foo 0  =  1
-foo x  =  foo (x - 1) - 1
-
-foo 0  =  1
-foo x  =  0 - foo (x - 1)
-
-foo 0  =  1
-foo x  =  1 - foo (x - 1)
-
-foo x  =  x * (x + x) - 1
-
-foo x  =  x * (x * x) - 1
-
-foo x  =  x * (x - 1) - 1
-
-foo x  =  x * (0 - x) - 1
-
-foo x  =  x * (1 - x) - 1
-
-foo x  =  x + (x * x - 1)
-
 foo x  =  x + (x + (x + x))
 
 foo x  =  x + (x + (x + 1))
@@ -396,6 +339,8 @@
 
 foo x  =  x + (1 - x * x)
 
+foo x  =  x + (x * x - 1)
+
 foo x  =  1 + (1 + (x + 1))
 
 foo x  =  1 + (1 + x * x)
@@ -412,8 +357,6 @@
 
 foo x  =  1 + (1 - x * x)
 
-foo x  =  x * (x * x - 1)
-
 foo x  =  x * (x + (x + x))
 
 foo x  =  x * (x + x * x)
@@ -438,8 +381,12 @@
 
 foo x  =  x * (1 - x * x)
 
+foo x  =  x * (x * x - 1)
+
 foo x  =  x - (1 + (x + 1))
 
+foo x  =  x - (1 + x * x)
+
 foo x  =  x - (1 + (1 - x))
 
 foo x  =  0 - (x + (x + x))
@@ -448,6 +395,8 @@
 
 foo x  =  0 - (1 + (x + 1))
 
+foo x  =  0 - (1 + x * x)
+
 foo x  =  0 - (1 + (1 - x))
 
 foo x  =  1 - (x + (x + x))
@@ -464,6 +413,12 @@
 
 foo x  =  x * x - (x + x)
 
+foo x  =  x * x - (x + 1)
+
+foo x  =  x * (x + x) - 1
+
+foo x  =  x * (x * x) - 1
+
 foo 1  =  0
 foo x  =  x + (x + x)
 
@@ -507,9 +462,6 @@
 foo x  =  1 - (x + x)
 
 foo 1  =  1
-foo x  =  x * x - 1
-
-foo 1  =  1
 foo x  =  x + (x + x)
 
 foo 1  =  1
@@ -551,7 +503,55 @@
 foo 1  =  1
 foo x  =  1 - x * x
 
+foo 1  =  1
+foo x  =  x * x - 1
 
+foo 0  =  0
+foo x  =  x + foo (x - 1)
+
+foo 0  =  0
+foo x  =  foo (x - 1) + 1
+
+foo 0  =  0
+foo x  =  x * foo (x - 1)
+
+foo 0  =  0
+foo x  =  x - foo (x - 1)
+
+foo 0  =  0
+foo x  =  foo (x - 1) - x
+
+foo 0  =  0
+foo x  =  foo (x - 1) - 1
+
+foo 0  =  0
+foo x  =  1 - foo (x - 1)
+
+foo 0  =  1
+foo x  =  x + foo (x - 1)
+
+foo 0  =  1
+foo x  =  foo (x - 1) + 1
+
+foo 0  =  1
+foo x  =  x * foo (x - 1)
+
+foo 0  =  1
+foo x  =  x - foo (x - 1)
+
+foo 0  =  1
+foo x  =  foo (x - 1) - x
+
+foo 0  =  1
+foo x  =  foo (x - 1) - 1
+
+foo 0  =  1
+foo x  =  0 - foo (x - 1)
+
+foo 0  =  1
+foo x  =  1 - foo (x - 1)
+
+
 Unique candidates for: ? :: Int -> Int -> Int
   pruning with 13/34 rules
   [3,8,25,71,205] candidates
@@ -624,6 +624,10 @@
 0 ? x  =  0
 x ? y  =  y
 
+x ? y  =  dec (dec x)
+
+x ? y  =  dec (dec y)
+
 x ? y  =  x + x
 
 x ? y  =  x + y
@@ -636,10 +640,6 @@
 
 x ? y  =  y * y
 
-x ? y  =  dec (dec x)
-
-x ? y  =  dec (dec y)
-
 x ? 0  =  x
 x ? y  =  dec x
 
@@ -694,16 +694,16 @@
 x ? 0  =  x
 x ? y  =  y
 
+x ? y  =  dec (dec (dec x))
+
+x ? y  =  dec (dec (dec y))
+
 x ? y  =  dec (x * x)
 
 x ? y  =  dec (x * y)
 
 x ? y  =  dec (y * y)
 
-x ? y  =  dec (dec (dec x))
-
-x ? y  =  dec (dec (dec y))
-
 x ? y  =  x + dec x
 
 x ? y  =  x + dec y
@@ -719,6 +719,12 @@
 x ? y  =  y * dec y
 
 x ? 0  =  x
+x ? y  =  dec (dec x)
+
+x ? 0  =  x
+x ? y  =  dec (dec y)
+
+x ? 0  =  x
 x ? y  =  x + x
 
 x ? 0  =  x
@@ -733,10 +739,10 @@
 x ? 0  =  x
 x ? y  =  y * y
 
-x ? 0  =  x
+x ? 0  =  0
 x ? y  =  dec (dec x)
 
-x ? 0  =  x
+x ? 0  =  0
 x ? y  =  dec (dec y)
 
 x ? 0  =  0
@@ -748,15 +754,18 @@
 x ? 0  =  0
 x ? y  =  x * x
 
-x ? 0  =  0
-x ? y  =  dec (dec x)
-
-x ? 0  =  0
-x ? y  =  dec (dec y)
-
 x ? 0  =  dec x
 x ? y  =  dec y
 
+x ? 0  =  dec (dec x)
+x ? y  =  x
+
+x ? 0  =  dec (dec x)
+x ? y  =  y
+
+x ? 0  =  dec (dec x)
+x ? y  =  0
+
 x ? 0  =  x + x
 x ? y  =  x
 
@@ -775,14 +784,11 @@
 x ? 0  =  x * x
 x ? y  =  0
 
-x ? 0  =  dec (dec x)
-x ? y  =  x
-
-x ? 0  =  dec (dec x)
-x ? y  =  y
+0 ? x  =  x
+x ? y  =  dec (dec x)
 
-x ? 0  =  dec (dec x)
-x ? y  =  0
+0 ? x  =  x
+x ? y  =  dec (dec y)
 
 0 ? x  =  x
 x ? y  =  x + x
@@ -799,10 +805,10 @@
 0 ? x  =  x
 x ? y  =  y * y
 
-0 ? x  =  x
+0 ? x  =  0
 x ? y  =  dec (dec x)
 
-0 ? x  =  x
+0 ? x  =  0
 x ? y  =  dec (dec y)
 
 0 ? x  =  0
@@ -814,40 +820,34 @@
 0 ? x  =  0
 x ? y  =  y * y
 
-0 ? x  =  0
-x ? y  =  dec (dec x)
-
-0 ? x  =  0
-x ? y  =  dec (dec y)
-
 0 ? x  =  dec x
 x ? y  =  dec x
 
-0 ? x  =  x + x
+0 ? x  =  dec (dec x)
 x ? y  =  x
 
-0 ? x  =  x + x
+0 ? x  =  dec (dec x)
 x ? y  =  y
 
-0 ? x  =  x + x
+0 ? x  =  dec (dec x)
 x ? y  =  0
 
-0 ? x  =  x * x
+0 ? x  =  x + x
 x ? y  =  x
 
-0 ? x  =  x * x
+0 ? x  =  x + x
 x ? y  =  y
 
-0 ? x  =  x * x
+0 ? x  =  x + x
 x ? y  =  0
 
-0 ? x  =  dec (dec x)
+0 ? x  =  x * x
 x ? y  =  x
 
-0 ? x  =  dec (dec x)
+0 ? x  =  x * x
 x ? y  =  y
 
-0 ? x  =  dec (dec x)
+0 ? x  =  x * x
 x ? y  =  0
 
 0 ? x  =  x
@@ -906,35 +906,9 @@
 x ? 0  =  0
 x ? y  =  x
 
-x ? 0  =  x
-x ? y  =  y ? dec x
-
-x ? 0  =  x
-x ? y  =  y ? dec y
-
-x ? 0  =  x
-x ? y  =  dec x ? x
-
-x ? 0  =  x
-x ? y  =  dec x ? y
-
-x ? 0  =  x
-x ? y  =  dec y ? x
-
-0 ? x  =  x
-x ? y  =  x ? dec y
-
-0 ? x  =  x
-x ? y  =  y ? dec x
-
-0 ? x  =  x
-x ? y  =  y ? dec y
-
-0 ? x  =  x
-x ? y  =  dec x ? x
+x ? y  =  dec (dec (dec (dec x)))
 
-0 ? x  =  x
-x ? y  =  dec y ? x
+x ? y  =  dec (dec (dec (dec y)))
 
 x ? y  =  dec (dec (x * x))
 
@@ -942,10 +916,6 @@
 
 x ? y  =  dec (dec (y * y))
 
-x ? y  =  dec (dec (dec (dec x)))
-
-x ? y  =  dec (dec (dec (dec y)))
-
 x ? y  =  dec (x * dec x)
 
 x ? y  =  dec (x * dec y)
@@ -954,6 +924,10 @@
 
 x ? y  =  dec (y * dec y)
 
+x ? y  =  x + dec (dec x)
+
+x ? y  =  x + dec (dec y)
+
 x ? y  =  x + (x + x)
 
 x ? y  =  x + (x + y)
@@ -966,9 +940,7 @@
 
 x ? y  =  x + y * y
 
-x ? y  =  x + dec (dec x)
-
-x ? y  =  x + dec (dec y)
+x ? y  =  y + dec (dec y)
 
 x ? y  =  y + (y + y)
 
@@ -978,8 +950,10 @@
 
 x ? y  =  y + y * y
 
-x ? y  =  y + dec (dec y)
+x ? y  =  x * dec (dec x)
 
+x ? y  =  x * dec (dec y)
+
 x ? y  =  x * (x + x)
 
 x ? y  =  x * (x + y)
@@ -992,9 +966,9 @@
 
 x ? y  =  x * (y * y)
 
-x ? y  =  x * dec (dec x)
+x ? y  =  y * dec (dec x)
 
-x ? y  =  x * dec (dec y)
+x ? y  =  y * dec (dec y)
 
 x ? y  =  y * (x + y)
 
@@ -1002,10 +976,6 @@
 
 x ? y  =  y * (y * y)
 
-x ? y  =  y * dec (dec x)
-
-x ? y  =  y * dec (dec y)
-
 x ? y  =  dec x * dec x
 
 x ? y  =  dec x * dec y
@@ -1013,19 +983,19 @@
 x ? y  =  dec y * dec y
 
 x ? 0  =  x
-x ? y  =  dec (x * x)
+x ? y  =  dec (dec (dec x))
 
 x ? 0  =  x
-x ? y  =  dec (x * y)
+x ? y  =  dec (dec (dec y))
 
 x ? 0  =  x
-x ? y  =  dec (y * y)
+x ? y  =  dec (x * x)
 
 x ? 0  =  x
-x ? y  =  dec (dec (dec x))
+x ? y  =  dec (x * y)
 
 x ? 0  =  x
-x ? y  =  dec (dec (dec y))
+x ? y  =  dec (y * y)
 
 x ? 0  =  x
 x ? y  =  x + dec x
@@ -1049,19 +1019,19 @@
 x ? y  =  y * dec y
 
 x ? 0  =  0
-x ? y  =  dec (x * x)
+x ? y  =  dec (dec (dec x))
 
 x ? 0  =  0
-x ? y  =  dec (x * y)
+x ? y  =  dec (dec (dec y))
 
 x ? 0  =  0
-x ? y  =  dec (y * y)
+x ? y  =  dec (x * x)
 
 x ? 0  =  0
-x ? y  =  dec (dec (dec x))
+x ? y  =  dec (x * y)
 
 x ? 0  =  0
-x ? y  =  dec (dec (dec y))
+x ? y  =  dec (y * y)
 
 x ? 0  =  0
 x ? y  =  x + dec x
@@ -1079,6 +1049,12 @@
 x ? y  =  x * dec y
 
 x ? 0  =  dec x
+x ? y  =  dec (dec x)
+
+x ? 0  =  dec x
+x ? y  =  dec (dec y)
+
+x ? 0  =  dec x
 x ? y  =  x + x
 
 x ? 0  =  dec x
@@ -1096,11 +1072,11 @@
 x ? 0  =  dec x
 x ? y  =  y * y
 
-x ? 0  =  dec x
-x ? y  =  dec (dec x)
+x ? 0  =  dec (dec x)
+x ? y  =  dec x
 
-x ? 0  =  dec x
-x ? y  =  dec (dec y)
+x ? 0  =  dec (dec x)
+x ? y  =  dec y
 
 x ? 0  =  x + x
 x ? y  =  dec x
@@ -1114,28 +1090,22 @@
 x ? 0  =  x * x
 x ? y  =  dec y
 
-x ? 0  =  dec (dec x)
-x ? y  =  dec x
-
-x ? 0  =  dec (dec x)
-x ? y  =  dec y
-
-x ? 0  =  dec (x * x)
+x ? 0  =  dec (dec (dec x))
 x ? y  =  x
 
-x ? 0  =  dec (x * x)
+x ? 0  =  dec (dec (dec x))
 x ? y  =  y
 
-x ? 0  =  dec (x * x)
+x ? 0  =  dec (dec (dec x))
 x ? y  =  0
 
-x ? 0  =  dec (dec (dec x))
+x ? 0  =  dec (x * x)
 x ? y  =  x
 
-x ? 0  =  dec (dec (dec x))
+x ? 0  =  dec (x * x)
 x ? y  =  y
 
-x ? 0  =  dec (dec (dec x))
+x ? 0  =  dec (x * x)
 x ? y  =  0
 
 x ? 0  =  x + dec x
@@ -1157,19 +1127,19 @@
 x ? y  =  0
 
 0 ? x  =  x
-x ? y  =  dec (x * x)
+x ? y  =  dec (dec (dec x))
 
 0 ? x  =  x
-x ? y  =  dec (x * y)
+x ? y  =  dec (dec (dec y))
 
 0 ? x  =  x
-x ? y  =  dec (y * y)
+x ? y  =  dec (x * x)
 
 0 ? x  =  x
-x ? y  =  dec (dec (dec x))
+x ? y  =  dec (x * y)
 
 0 ? x  =  x
-x ? y  =  dec (dec (dec y))
+x ? y  =  dec (y * y)
 
 0 ? x  =  x
 x ? y  =  x + dec x
@@ -1193,19 +1163,19 @@
 x ? y  =  y * dec y
 
 0 ? x  =  0
-x ? y  =  dec (x * x)
+x ? y  =  dec (dec (dec x))
 
 0 ? x  =  0
-x ? y  =  dec (x * y)
+x ? y  =  dec (dec (dec y))
 
 0 ? x  =  0
-x ? y  =  dec (y * y)
+x ? y  =  dec (x * x)
 
 0 ? x  =  0
-x ? y  =  dec (dec (dec x))
+x ? y  =  dec (x * y)
 
 0 ? x  =  0
-x ? y  =  dec (dec (dec y))
+x ? y  =  dec (y * y)
 
 0 ? x  =  0
 x ? y  =  x + dec x
@@ -1223,6 +1193,12 @@
 x ? y  =  y * dec y
 
 0 ? x  =  dec x
+x ? y  =  dec (dec x)
+
+0 ? x  =  dec x
+x ? y  =  dec (dec y)
+
+0 ? x  =  dec x
 x ? y  =  x + x
 
 0 ? x  =  dec x
@@ -1240,11 +1216,11 @@
 0 ? x  =  dec x
 x ? y  =  y * y
 
-0 ? x  =  dec x
-x ? y  =  dec (dec x)
+0 ? x  =  dec (dec x)
+x ? y  =  dec x
 
-0 ? x  =  dec x
-x ? y  =  dec (dec y)
+0 ? x  =  dec (dec x)
+x ? y  =  dec y
 
 0 ? x  =  x + x
 x ? y  =  dec x
@@ -1258,28 +1234,22 @@
 0 ? x  =  x * x
 x ? y  =  dec y
 
-0 ? x  =  dec (dec x)
-x ? y  =  dec x
-
-0 ? x  =  dec (dec x)
-x ? y  =  dec y
-
-0 ? x  =  dec (x * x)
+0 ? x  =  dec (dec (dec x))
 x ? y  =  x
 
-0 ? x  =  dec (x * x)
+0 ? x  =  dec (dec (dec x))
 x ? y  =  y
 
-0 ? x  =  dec (x * x)
+0 ? x  =  dec (dec (dec x))
 x ? y  =  0
 
-0 ? x  =  dec (dec (dec x))
+0 ? x  =  dec (x * x)
 x ? y  =  x
 
-0 ? x  =  dec (dec (dec x))
+0 ? x  =  dec (x * x)
 x ? y  =  y
 
-0 ? x  =  dec (dec (dec x))
+0 ? x  =  dec (x * x)
 x ? y  =  0
 
 0 ? x  =  x + dec x
@@ -1302,6 +1272,14 @@
 
 0 ? x  =  x
 x ? 0  =  x
+x ? y  =  dec (dec x)
+
+0 ? x  =  x
+x ? 0  =  x
+x ? y  =  dec (dec y)
+
+0 ? x  =  x
+x ? 0  =  x
 x ? y  =  x + x
 
 0 ? x  =  x
@@ -1321,11 +1299,11 @@
 x ? y  =  y * y
 
 0 ? x  =  x
-x ? 0  =  x
+x ? 0  =  0
 x ? y  =  dec (dec x)
 
 0 ? x  =  x
-x ? 0  =  x
+x ? 0  =  0
 x ? y  =  dec (dec y)
 
 0 ? x  =  x
@@ -1337,83 +1315,75 @@
 x ? y  =  x * x
 
 0 ? x  =  x
-x ? 0  =  0
-x ? y  =  dec (dec x)
-
-0 ? x  =  x
-x ? 0  =  0
-x ? y  =  dec (dec y)
-
-0 ? x  =  x
 x ? 0  =  dec x
 x ? y  =  dec y
 
 0 ? x  =  x
-x ? 0  =  x + x
+x ? 0  =  dec (dec x)
 x ? y  =  x
 
 0 ? x  =  x
-x ? 0  =  x + x
+x ? 0  =  dec (dec x)
 x ? y  =  0
 
 0 ? x  =  x
-x ? 0  =  x * x
+x ? 0  =  x + x
 x ? y  =  x
 
 0 ? x  =  x
-x ? 0  =  x * x
+x ? 0  =  x + x
 x ? y  =  0
 
 0 ? x  =  x
-x ? 0  =  dec (dec x)
+x ? 0  =  x * x
 x ? y  =  x
 
 0 ? x  =  x
-x ? 0  =  dec (dec x)
+x ? 0  =  x * x
 x ? y  =  0
 
 0 ? x  =  0
 x ? 0  =  x
-x ? y  =  y + y
+x ? y  =  dec (dec x)
 
 0 ? x  =  0
 x ? 0  =  x
-x ? y  =  y * y
+x ? y  =  dec (dec y)
 
 0 ? x  =  0
 x ? 0  =  x
-x ? y  =  dec (dec x)
+x ? y  =  y + y
 
 0 ? x  =  0
 x ? 0  =  x
-x ? y  =  dec (dec y)
+x ? y  =  y * y
 
 0 ? x  =  0
 x ? 0  =  0
-x ? y  =  x + y
+x ? y  =  dec (dec x)
 
 0 ? x  =  0
 x ? 0  =  0
-x ? y  =  dec (dec x)
+x ? y  =  dec (dec y)
 
 0 ? x  =  0
 x ? 0  =  0
-x ? y  =  dec (dec y)
+x ? y  =  x + y
 
 0 ? x  =  0
 x ? 0  =  dec x
 x ? y  =  dec y
 
 0 ? x  =  0
-x ? 0  =  x + x
+x ? 0  =  dec (dec x)
 x ? y  =  y
 
 0 ? x  =  0
-x ? 0  =  x * x
+x ? 0  =  x + x
 x ? y  =  y
 
 0 ? x  =  0
-x ? 0  =  dec (dec x)
+x ? 0  =  x * x
 x ? y  =  y
 
 0 ? x  =  dec x
@@ -1436,39 +1406,39 @@
 x ? 0  =  dec x
 x ? y  =  0
 
-0 ? x  =  x + x
+0 ? x  =  dec (dec x)
 x ? 0  =  x
 x ? y  =  y
 
-0 ? x  =  x + x
+0 ? x  =  dec (dec x)
 x ? 0  =  x
 x ? y  =  0
 
-0 ? x  =  x + x
+0 ? x  =  dec (dec x)
 x ? 0  =  0
 x ? y  =  x
 
-0 ? x  =  x * x
+0 ? x  =  x + x
 x ? 0  =  x
 x ? y  =  y
 
-0 ? x  =  x * x
+0 ? x  =  x + x
 x ? 0  =  x
 x ? y  =  0
 
-0 ? x  =  x * x
+0 ? x  =  x + x
 x ? 0  =  0
 x ? y  =  x
 
-0 ? x  =  dec (dec x)
+0 ? x  =  x * x
 x ? 0  =  x
 x ? y  =  y
 
-0 ? x  =  dec (dec x)
+0 ? x  =  x * x
 x ? 0  =  x
 x ? y  =  0
 
-0 ? x  =  dec (dec x)
+0 ? x  =  x * x
 x ? 0  =  0
 x ? y  =  x
 
@@ -1476,7 +1446,37 @@
 0 ? x  =  dec x
 x ? y  =  dec x
 
+x ? 0  =  x
+x ? y  =  y ? dec x
 
+x ? 0  =  x
+x ? y  =  y ? dec y
+
+x ? 0  =  x
+x ? y  =  dec x ? x
+
+x ? 0  =  x
+x ? y  =  dec x ? y
+
+x ? 0  =  x
+x ? y  =  dec y ? x
+
+0 ? x  =  x
+x ? y  =  x ? dec y
+
+0 ? x  =  x
+x ? y  =  y ? dec x
+
+0 ? x  =  x
+x ? y  =  y ? dec y
+
+0 ? x  =  x
+x ? y  =  dec x ? x
+
+0 ? x  =  x
+x ? y  =  dec y ? x
+
+
 Unique candidates for: goo :: [Int] -> [Int]
   pruning with 4/4 rules
   [2,1,1,2,4,7,10] candidates
@@ -1505,14 +1505,14 @@
 goo []  =  []
 goo (x:xs)  =  xs ++ xs
 
+goo xs  =  xs ++ (xs ++ xs)
+
 goo []  =  []
 goo (x:xs)  =  xs ++ goo xs
 
 goo []  =  []
 goo (x:xs)  =  goo xs ++ xs
 
-goo xs  =  xs ++ (xs ++ xs)
-
 goo []  =  []
 goo (x:xs)  =  x:x:xs
 
@@ -1531,6 +1531,8 @@
 goo []  =  []
 goo (x:xs)  =  xs ++ (xs ++ xs)
 
+goo xs  =  xs ++ (xs ++ (xs ++ xs))
+
 goo []  =  []
 goo (x:xs)  =  x:x:goo xs
 
@@ -1558,9 +1560,7 @@
 goo []  =  []
 goo (x:xs)  =  goo xs ++ (xs ++ xs)
 
-goo xs  =  xs ++ (xs ++ (xs ++ xs))
 
-
 Unique candidates for: ?? :: [Int] -> [Int] -> [Int]
   pruning with 4/4 rules
   [3,8,15,43,122] candidates
@@ -1657,12 +1657,6 @@
 (x:xs) ?? ys  =  []
 
 xs ?? []  =  xs
-xs ?? (x:ys)  =  ys ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? ys  =  ys ?? xs
-
-xs ?? []  =  xs
 xs ?? (x:ys)  =  x:xs
 
 xs ?? []  =  xs
@@ -1763,62 +1757,12 @@
 (x:xs) ?? []  =  xs
 (x:xs) ?? (y:ys)  =  []
 
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? []
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  xs ?? ys
+xs ?? []  =  xs
+xs ?? (x:ys)  =  ys ?? xs
 
 [] ?? xs  =  xs
-(x:xs) ?? []  =  []
-(x:xs) ?? (y:ys)  =  ys ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  xs ?? ys
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs
-(x:xs) ?? (y:ys)  =  ys ?? xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  xs
-
-[] ?? xs  =  []
-(x:xs) ?? []  =  xs ?? xs
-(x:xs) ?? (y:ys)  =  ys
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
 (x:xs) ?? ys  =  ys ?? xs
 
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs
-(x:xs) ?? ys  =  [] ?? xs
-
-[] ?? []  =  []
-[] ?? (x:xs)  =  xs ?? xs
-(x:xs) ?? ys  =  xs
-
 xs ?? ys  =  xs ++ (xs ++ xs)
 
 xs ?? ys  =  xs ++ (xs ++ ys)
@@ -2102,6 +2046,62 @@
 [] ?? []  =  []
 [] ?? (x:xs)  =  xs ++ xs
 (x:xs) ?? ys  =  []
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  xs ?? []
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys ?? xs
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys ?? []
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  xs ?? xs
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  xs ?? xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  []
+(x:xs) ?? (y:ys)  =  xs ?? ys
+
+[] ?? xs  =  xs
+(x:xs) ?? []  =  []
+(x:xs) ?? (y:ys)  =  ys ?? xs
+
+[] ?? xs  =  []
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  xs ?? ys
+
+[] ?? xs  =  []
+(x:xs) ?? []  =  xs
+(x:xs) ?? (y:ys)  =  ys ?? xs
+
+[] ?? xs  =  []
+(x:xs) ?? []  =  xs ?? xs
+(x:xs) ?? (y:ys)  =  xs
+
+[] ?? xs  =  []
+(x:xs) ?? []  =  xs ?? xs
+(x:xs) ?? (y:ys)  =  ys
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? ys  =  ys ?? xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs
+(x:xs) ?? ys  =  [] ?? xs
+
+[] ?? []  =  []
+[] ?? (x:xs)  =  xs ?? xs
+(x:xs) ?? ys  =  xs
 
 
 Unique candidates for: ton :: Bool -> Bool
diff --git a/bench/weird.hs b/bench/weird.hs
--- a/bench/weird.hs
+++ b/bench/weird.hs
@@ -19,8 +19,19 @@
 x ^^^ 0  =  x
 _ ^^^ _  =  0
 
+-- | inc or square based on boolean argument
+--   except for 0 where the answer is swapped
+isq :: Bool -> Int -> Int
+isq False 0  =  0
+isq True  0  =  1
+isq False x  =  x + 1
+isq True  x  =  x * x
+
 main :: IO ()
 main  =  do
+  -- TODO: Conjure should find isq, but doesn't due to overpruning
+  conjure "isq" isq ingredients
+
   conjure "^^^" (^^^)   ingredients
   conjure "^^^" (^^^) $ ingredients ++ [singlePattern]
 
@@ -31,8 +42,8 @@
 
 ingredients :: [Ingredient]
 ingredients  =
-  [ unfun (0::Int)
-  , unfun (1::Int)
+  [ con (0::Int)
+  , con (1::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
   , fun "==" ((==) :: Int -> Int -> Bool)
diff --git a/bench/weird.txt b/bench/weird.txt
--- a/bench/weird.txt
+++ b/bench/weird.txt
@@ -1,10 +1,27 @@
+isq :: Bool -> Int -> Int
+-- testing 360 combinations of argument values
+-- pruning with 56/91 rules
+-- 3 candidates of size 1
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- 6 candidates of size 4
+-- 8 candidates of size 5
+-- 48 candidates of size 6
+-- 63 candidates of size 7
+-- 301 candidates of size 8
+-- tested 432 candidates
+isq False 0  =  0
+isq False x  =  x + 1
+isq True 0  =  1
+isq True x  =  x * x
+
 (^^^) :: Int -> Int -> Int
 -- testing 360 combinations of argument values
 -- pruning with 56/91 rules
 -- 4 candidates of size 1
--- 6 candidates of size 2
--- 10 candidates of size 3
--- tested 19 candidates
+-- 0 candidates of size 2
+-- 9 candidates of size 3
+-- tested 13 candidates
 0 ^^^ x  =  x
 x ^^^ 0  =  x
 x ^^^ y  =  0
@@ -22,7 +39,7 @@
 -- 996 candidates of size 8
 -- 1266 candidates of size 9
 -- 11700 candidates of size 10
--- tested 6683 candidates
+-- tested 11507 candidates
 x ^^^ y  =  if 0 == x * y
             then x + y
             else 0
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -2,6 +2,19 @@
 ============================
 
 
+v0.7.6 (August 2025)
+--------------------
+
+* Flip-flop: `con` replaces `unfun`.
+* Allow chains of guards, or multiple guards.
+* Replace `omitEarlyTests` by `maxEarlyTests`, defaulting to 12.
+* Improve pruning through early tests.
+* Fix `requireDescent` switch
+* Fix overpruning in early tests.
+* Refactor parts of `Engine.candidateDefnsC`.
+* Cleanup built-in examples.
+
+
 v0.7.4 (May 2025)
 -----------------
 
diff --git a/code-conjure.cabal b/code-conjure.cabal
--- a/code-conjure.cabal
+++ b/code-conjure.cabal
@@ -3,7 +3,7 @@
 -- Copyright (C) 2021-2025 Rudy Matela
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 name:                code-conjure
-version:             0.7.4
+version:             0.7.6
 synopsis:            synthesize Haskell functions out of partial definitions
 description:
   Conjure is a tool that synthesizes Haskell functions out of partial definitions.
@@ -58,7 +58,6 @@
            , GHC==9.8
            , GHC==9.6
            , GHC==9.4
-           , GHC==9.2
            , GHC==9.0
            , GHC==8.8
 
@@ -69,7 +68,7 @@
 source-repository this
   type:            git
   location:        https://github.com/rudymatela/conjure
-  tag:             v0.7.4
+  tag:             v0.7.6
 
 library
   exposed-modules: Conjure
diff --git a/eg/arith.hs b/eg/arith.hs
--- a/eg/arith.hs
+++ b/eg/arith.hs
@@ -48,8 +48,8 @@
 
 ingredients :: [Ingredient]
 ingredients =
-  [ unfun (0::Int)
-  , unfun (1::Int)
+  [ con (0::Int)
+  , con (1::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
   ]
diff --git a/eg/arith.txt b/eg/arith.txt
--- a/eg/arith.txt
+++ b/eg/arith.txt
@@ -2,61 +2,61 @@
 -- testing 4 combinations of argument values
 -- pruning with 14/25 rules
 -- 3 candidates of size 1
--- 1 candidates of size 2
--- 6 candidates of size 3
--- tested 5 candidates
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- tested 4 candidates
 double x  =  x + x
 
 triple :: Int -> Int
 -- testing 4 combinations of argument values
 -- pruning with 14/25 rules
 -- 3 candidates of size 1
--- 1 candidates of size 2
--- 6 candidates of size 3
--- 2 candidates of size 4
--- 11 candidates of size 5
--- tested 13 candidates
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- 0 candidates of size 4
+-- 8 candidates of size 5
+-- tested 7 candidates
 triple x  =  x + (x + x)
 
 add :: Int -> Int -> Int
 -- testing 4 combinations of argument values
 -- pruning with 14/25 rules
 -- 4 candidates of size 1
--- 6 candidates of size 2
--- 10 candidates of size 3
--- tested 12 candidates
+-- 0 candidates of size 2
+-- 8 candidates of size 3
+-- tested 6 candidates
 add x y  =  x + y
 
 square :: Int -> Int
 -- testing 3 combinations of argument values
 -- pruning with 14/25 rules
 -- 3 candidates of size 1
--- 1 candidates of size 2
--- 4 candidates of size 3
--- tested 7 candidates
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- tested 6 candidates
 square x  =  x * x
 
 cube :: Int -> Int
 -- testing 3 combinations of argument values
 -- pruning with 14/25 rules
 -- 3 candidates of size 1
--- 1 candidates of size 2
--- 4 candidates of size 3
--- 1 candidates of size 4
--- 10 candidates of size 5
--- tested 17 candidates
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- 0 candidates of size 4
+-- 8 candidates of size 5
+-- tested 14 candidates
 cube x  =  x * (x * x)
 
 tnpo :: Int -> Int
 -- testing 3 combinations of argument values
 -- pruning with 14/25 rules
 -- 3 candidates of size 1
--- 2 candidates of size 2
--- 6 candidates of size 3
--- 4 candidates of size 4
--- 11 candidates of size 5
--- 7 candidates of size 6
--- 35 candidates of size 7
--- tested 35 candidates
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- 0 candidates of size 4
+-- 8 candidates of size 5
+-- 0 candidates of size 6
+-- 27 candidates of size 7
+-- tested 16 candidates
 tnpo x  =  x + (x + (x + 1))
 
diff --git a/eg/bits.hs b/eg/bits.hs
--- a/eg/bits.hs
+++ b/eg/bits.hs
@@ -19,8 +19,8 @@
 main :: IO ()
 main  =  do
   conjure "bitsum" bitsum
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "halve" ((`div` 2) :: Int -> Int)
     , fun "parity" ((`mod` 2) :: Int -> Int)
     , fun "+" ((+) :: Int -> Int -> Int)
@@ -29,9 +29,9 @@
   -- bitsum n  =  parity n + bitsum (halve n)
 
   conjure "bitsum" bitsum
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , unfun (2 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , con (2 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "`div`" (div :: Int -> Int -> Int)
     , fun "`mod`" (mod :: Int -> Int -> Int)
diff --git a/eg/bits.txt b/eg/bits.txt
--- a/eg/bits.txt
+++ b/eg/bits.txt
@@ -2,13 +2,13 @@
 -- testing 8 combinations of argument values
 -- pruning with 21/25 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 5 candidates of size 3
--- 10 candidates of size 4
--- 26 candidates of size 5
--- 68 candidates of size 6
--- 182 candidates of size 7
--- tested 145 candidates
+-- 2 candidates of size 2
+-- 4 candidates of size 3
+-- 8 candidates of size 4
+-- 19 candidates of size 5
+-- 56 candidates of size 6
+-- 152 candidates of size 7
+-- tested 216 candidates
 bitsum 0  =  0
 bitsum x  =  parity x + bitsum (halve x)
 
@@ -16,15 +16,15 @@
 -- testing 8 combinations of argument values
 -- pruning with 27/32 rules
 -- 4 candidates of size 1
--- 2 candidates of size 2
--- 17 candidates of size 3
--- 16 candidates of size 4
--- 246 candidates of size 5
--- 239 candidates of size 6
--- 4504 candidates of size 7
--- 4542 candidates of size 8
--- 89215 candidates of size 9
--- tested 10191 candidates
+-- 0 candidates of size 2
+-- 15 candidates of size 3
+-- 0 candidates of size 4
+-- 233 candidates of size 5
+-- 0 candidates of size 6
+-- 4297 candidates of size 7
+-- 72 candidates of size 8
+-- 85204 candidates of size 9
+-- tested 88434 candidates
 bitsum 0  =  0
 bitsum x  =  x `mod` 2 + bitsum (x `div` 2)
 
diff --git a/eg/bools.hs b/eg/bools.hs
--- a/eg/bools.hs
+++ b/eg/bools.hs
@@ -25,8 +25,8 @@
 
 ingredients :: [Ingredient]
 ingredients =
-  [ unfun False
-  , unfun True
+  [ con False
+  , con True
   , fun "not" not
   , fun "||" (||)
   , fun "&&" (&&)
diff --git a/eg/bools.txt b/eg/bools.txt
--- a/eg/bools.txt
+++ b/eg/bools.txt
@@ -5,8 +5,8 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 2 candidates of size 4
--- 4 candidates of size 5
--- tested 8 candidates
+-- 2 candidates of size 5
+-- tested 6 candidates
 and []  =  True
 and (p:ps)  =  p && and ps
 
@@ -17,7 +17,7 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 2 candidates of size 4
--- 4 candidates of size 5
+-- 2 candidates of size 5
 -- tested 5 candidates
 or []  =  False
 or (p:ps)  =  p || or ps
@@ -29,7 +29,7 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 4 candidates of size 4
--- tested 6 candidates
+-- tested 4 candidates
 and  =  foldr (&&) True
 
 or :: [Bool] -> Bool
@@ -39,6 +39,6 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 4 candidates of size 4
--- tested 5 candidates
+-- tested 3 candidates
 or  =  foldr (||) False
 
diff --git a/eg/bst.hs b/eg/bst.hs
--- a/eg/bst.hs
+++ b/eg/bst.hs
@@ -123,7 +123,7 @@
 main :: IO ()
 main = do
   conjure "mem" mem
-    [ unfun False
+    [ con False
     , fun "||" (||)
     , fun "==" ((==) :: Int -> Int -> Bool)
     , fun "<" ((<) :: Int -> Int -> Bool)
@@ -131,15 +131,15 @@
     ]
 
   conjure "mem" mem
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "`compare`" (compare :: Int -> Int -> Ordering)
     , ordcase (undefined :: Bool)
     ]
 
   -- simply out of reach performance-wise (reaching 16 but need size 22)
   conjure "insert" insert
-    [ unfun Leaf
+    [ con Leaf
     , fun "Node" Node
     , fun "unit" unit
     , fun "`compare`" (compare :: Int -> Int -> Ordering)
@@ -150,7 +150,7 @@
   -- reachable in 15s, candidate #32878 at size 14.
   -- increase target to 50400 to reach...
   conjureFromSpec "before" beforeSpec
-    [ unfun Leaf
+    [ con Leaf
     , fun "Node" Node
     , fun "==" ((==) :: Int -> Int -> Bool)
     , fun "<" ((<) :: Int -> Int -> Bool)
@@ -161,7 +161,7 @@
   -- reachable in 14s, candidate #32747 at size 14.
   -- increase target to 50400 to reach...
   conjureFromSpec "beyond" beyondSpec
-    [ unfun Leaf
+    [ con Leaf
     , fun "Node" Node
     , fun "==" ((==) :: Int -> Int -> Bool)
     , fun "<=" ((<) :: Int -> Int -> Bool)
@@ -172,7 +172,7 @@
   -- with 15, this reaches the solution, using 12 for shorter runtime
   -- using maxEquationSize = 7 reduces runtime from 13s to 11s
   conjureFromSpec "before" beforeSpec
-    [ unfun Leaf
+    [ con Leaf
     , fun "Node" Node
     , fun "`compare`" (compare :: Int -> Int -> Ordering)
     , ordcase (undefined :: Tree)
@@ -183,7 +183,7 @@
   -- with 15, this reaches the solution, using 12 for shorter runtime
   -- using maxEquationSize = 7 reduces runtime from 13s to 11s
   conjureFromSpec "beyond" beyondSpec
-    [ unfun Leaf
+    [ con Leaf
     , fun "Node" Node
     , fun "`compare`" (compare :: Int -> Int -> Ordering)
     , ordcase (undefined :: Tree)
@@ -193,7 +193,7 @@
 
   -- reachable in 55s, candidate #173109 at size 13.
   conjure "union" union
-    [ unfun Leaf
+    [ con Leaf
     , fun "Node" Node
     , fun "before" before
     , fun "beyond" beyond
diff --git a/eg/bst.txt b/eg/bst.txt
--- a/eg/bst.txt
+++ b/eg/bst.txt
@@ -9,11 +9,11 @@
 -- 0 candidates of size 6
 -- 0 candidates of size 7
 -- 24 candidates of size 8
--- 72 candidates of size 9
+-- 48 candidates of size 9
 -- 0 candidates of size 10
--- 240 candidates of size 11
--- 96 candidates of size 12
--- tested 362 candidates
+-- 180 candidates of size 11
+-- 80 candidates of size 12
+-- tested 274 candidates
 mem x Leaf  =  False
 mem x (Node t1 y t2)  =  mem x t1 || (x == y || mem x t2)
 
@@ -29,10 +29,10 @@
 -- 6 candidates of size 7
 -- 0 candidates of size 8
 -- 0 candidates of size 9
--- 192 candidates of size 10
+-- 32 candidates of size 10
 -- 0 candidates of size 11
--- 384 candidates of size 12
--- tested 346 candidates
+-- 160 candidates of size 12
+-- tested 106 candidates
 mem x Leaf  =  False
 mem x (Node t1 y t2)  =  case x `compare` y of
                          LT -> mem x t1
@@ -51,10 +51,10 @@
 -- 26 candidates of size 7
 -- 0 candidates of size 8
 -- 0 candidates of size 9
--- 200 candidates of size 10
+-- 176 candidates of size 10
 -- 0 candidates of size 11
 -- 32 candidates of size 12
--- tested 264 candidates
+-- tested 240 candidates
 insert  =  undefined  -- search exhausted
 
 before :: Int -> Tree -> Tree
@@ -132,10 +132,10 @@
 -- 22 candidates of size 4
 -- 0 candidates of size 5
 -- 68 candidates of size 6
--- 240 candidates of size 7
+-- 152 candidates of size 7
 -- 82 candidates of size 8
--- 3018 candidates of size 9
--- 8098 candidates of size 10
--- tested 11531 candidates
+-- 2438 candidates of size 9
+-- 3970 candidates of size 10
+-- tested 6735 candidates
 union  =  undefined  -- search exhausted
 
diff --git a/eg/colin/IntFuns.hs b/eg/colin/IntFuns.hs
--- a/eg/colin/IntFuns.hs
+++ b/eg/colin/IntFuns.hs
@@ -15,7 +15,7 @@
 triIngredients :: [Ingredient]
 triIngredients =
   [ fun "==" ((==) :: Int -> Int -> Bool)
-  , unfun (1::Int)
+  , con (1::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "dec" ((\x -> x-1) :: Int -> Int)
   ]
@@ -37,8 +37,8 @@
 fibIngredients :: [Ingredient]
 fibIngredients =
   [ fun "<=" ((<=) :: Int -> Int -> Bool)
-  , unfun (0::Int)
-  , unfun (1::Int)
+  , con (0::Int)
+  , con (1::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "dec" ((\x -> x-1) :: Int -> Int)
   ]
@@ -79,7 +79,7 @@
   [ fun "==" ((==) :: [Int] -> [Int] -> Bool)
   , fun "factors" ((\n -> filter (\k -> n `mod` k == 0) [1..n]) :: Int -> [Int])
   , fun "list2" ((\i j -> [i,j]) :: Int -> Int -> [Int])
-  , unfun (1 :: Int)
+  , con (1 :: Int)
   ]
 
 -- looking through 38 candidates, 100% match, 7/7 assignments
diff --git a/eg/colin/ListFuns.hs b/eg/colin/ListFuns.hs
--- a/eg/colin/ListFuns.hs
+++ b/eg/colin/ListFuns.hs
@@ -13,7 +13,7 @@
 
 sumBackground :: [Ingredient]
 sumBackground =
-  [ unfun (0::Int)
+  [ con (0::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   ]
 
@@ -44,7 +44,7 @@
 
 memBackground :: [Ingredient]
 memBackground =
-  [ unfun False
+  [ con False
   , fun "==" ((==) :: Int -> Int -> Bool)
   , fun "&&" ((&&) :: Bool -> Bool -> Bool)
   , fun "||" ((||) :: Bool -> Bool -> Bool)
@@ -69,8 +69,8 @@
 
 subBackground :: [Ingredient]
 subBackground  =
-  [ unfun True
-  , unfun False
+  [ con True
+  , con False
   , fun ":" ((:) :: Int -> [Int] -> [Int])
   , fun "==" ((==) :: Int -> Int -> Bool)
   , iif (undefined :: Bool)
@@ -112,9 +112,9 @@
 
 takeBackground :: [Ingredient]
 takeBackground  =
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
-  , unfun ([] :: [A])
+  [ con (0 :: Int)
+  , con (1 :: Int)
+  , con ([] :: [A])
   , fun "-" ((-) :: Int -> Int -> Int)
   , fun ":" ((:) :: A -> [A] -> [A])
   ]
@@ -134,9 +134,9 @@
 
 dropBackground :: [Ingredient]
 dropBackground  =
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
-  , unfun ([] :: [A])
+  [ con (0 :: Int)
+  , con (1 :: Int)
+  , con ([] :: [A])
   , fun "-" ((-) :: Int -> Int -> Int)
   ]
 
@@ -155,7 +155,7 @@
 
 ordBackground :: [Ingredient]
 ordBackground  =
-  [ unfun True
+  [ con True
   , fun "null" (null :: [Int] -> Bool)
   , fun "head" (head :: [Int] -> Int)
   , fun "<=" ((<=) :: Int -> Int -> Bool)
@@ -179,7 +179,7 @@
 mergeBackground :: [Ingredient]
 mergeBackground  =
   [ fun "<=" ((<=) :: Int -> Int -> Bool)
-  , unfun ([] :: [Int])
+  , con ([] :: [Int])
   , fun ":" ((:) :: Int -> [Int] -> [Int])
   , iif (undefined :: [Int])
   ]
@@ -197,7 +197,7 @@
 
 zipBackground :: [Ingredient]
 zipBackground  =
-  [ unfun ([] :: [(A,B)])
+  [ con ([] :: [(A,B)])
   , fun "(,)" ((,) :: A -> B -> (A,B))
   , fun ":" ((:) :: (A,B) -> [(A,B)] -> [(A,B)])
   ]
@@ -214,7 +214,7 @@
 
 assocsBackground :: [Ingredient]
 assocsBackground  =
-  [ unfun ([] :: [A])
+  [ con ([] :: [A])
   , fun "==" ((==) :: Int -> Int -> Bool)
   , fun ":" ((:) :: A -> [A] -> [A])
   , fun "fst" (fst :: (Int,A) -> Int)
diff --git a/eg/conditionals.hs b/eg/conditionals.hs
new file mode 100644
--- /dev/null
+++ b/eg/conditionals.hs
@@ -0,0 +1,105 @@
+-- conditionals.hs: assorted functions involving conditionals
+--
+-- Copyright (C) 2021-2025 Rudy Matela
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+import Conjure
+
+negate' :: Int -> Int
+negate' 1  =  -1
+negate' 2  =  -2
+negate' (-1)  =   1
+negate' (-2)  =   2
+
+abs' :: Int -> Int
+abs' 1  =  1
+abs' 2  =  2
+abs' (-1)  =  1
+abs' (-2)  =  2
+
+signum' :: Int -> Int
+signum' 0  =  0
+signum' 1  =  1
+signum' 2  =  1
+signum' 3  =  1
+signum' (-1)  =  -1
+signum' (-2)  =  -1
+signum' (-3)  =  -1
+
+compare' :: Int -> Int -> Ordering
+compare' 0 0  =  EQ
+compare' 1 1  =  EQ
+compare' 2 2  =  EQ
+compare' 0 1  =  LT
+compare' 1 2  =  LT
+compare' 1 0  =  GT
+compare' 2 1  =  GT
+compare' (-1) 0  =  LT
+compare' 0 (-1)  =  GT
+
+min' :: Int -> Int -> Int -> Int
+min' 0 1 2  =  0
+min' 0 2 1  =  0
+min' 2 3 1  =  1
+min' 1 0 2  =  0
+min' 4 3 1  =  1
+min' 4 1 3  =  1
+
+max' :: Int -> Int -> Int -> Int
+max' 0 1 2  =  2
+max' 0 2 1  =  2
+max' 2 3 1  =  3
+max' 1 0 2  =  2
+max' 4 3 1  =  4
+max' 4 1 3  =  4
+
+median' :: Int -> Int -> Int -> Int
+median' 0 1 2  =  1
+median' 0 2 1  =  1
+median' 2 3 1  =  2
+median' 1 0 2  =  1
+median' 4 3 1  =  3
+median' 4 1 3  =  3
+
+main :: IO ()
+main = do
+  conjure "negate"  negate' ingredients
+  conjure "abs"     abs'    ingredients
+  conjure "signum"  signum' ingredients
+  conjure "compare" compare' compareIngredients
+
+  conjure "min" min' mmmIngredients
+  conjure "max" max' mmmIngredients
+  -- median is unreachable performance-wise with ifs
+  -- conjure "median" median' mmmIngredients
+  -- it is reachale with max and min on the background though...
+  -- (cf. bench/gps, #27 Median)
+
+ingredients :: [Ingredient]
+ingredients  =
+  [ con (0::Int)
+  , con (1::Int)
+  , con (-1::Int)
+  , fun "+" ((+) :: Int -> Int -> Int)
+  , fun "-" ((-) :: Int -> Int -> Int)
+  , fun "*" ((*) :: Int -> Int -> Int)
+  , fun "<"  ((<)  :: Int -> Int -> Bool)
+  , guard
+  ]
+
+compareIngredients :: [Ingredient]
+compareIngredients  =
+  [ con EQ
+  , con LT
+  , con GT
+  , fun "==" ((==) :: Int -> Int -> Bool)
+  , fun "<"  ((<)  :: Int -> Int -> Bool)
+--, fun "<=" ((<=) :: Int -> Int -> Bool)
+  , guard
+  ]
+
+mmmIngredients :: [Ingredient]
+mmmIngredients  =
+  [ fun "<=" ((<=) :: Int -> Int -> Bool)
+  , iif (undefined :: Int)
+  , target 50400
+  ]
diff --git a/eg/conditionals.txt b/eg/conditionals.txt
new file mode 100644
--- /dev/null
+++ b/eg/conditionals.txt
@@ -0,0 +1,109 @@
+negate :: Int -> Int
+-- testing 4 combinations of argument values
+-- pruning with 64/99 rules
+-- 4 candidates of size 1
+-- 0 candidates of size 2
+-- 5 candidates of size 3
+-- tested 8 candidates
+negate x  =  0 - x
+
+abs :: Int -> Int
+-- testing 4 combinations of argument values
+-- pruning with 64/99 rules
+-- 4 candidates of size 1
+-- 0 candidates of size 2
+-- 5 candidates of size 3
+-- 0 candidates of size 4
+-- 19 candidates of size 5
+-- 48 candidates of size 6
+-- 109 candidates of size 7
+-- 253 candidates of size 8
+-- tested 249 candidates
+abs x
+  | 0 < x  =  x
+  | otherwise  =  0 - x
+
+signum :: Int -> Int
+-- testing 7 combinations of argument values
+-- pruning with 64/99 rules
+-- 4 candidates of size 1
+-- 0 candidates of size 2
+-- 5 candidates of size 3
+-- 0 candidates of size 4
+-- 19 candidates of size 5
+-- 48 candidates of size 6
+-- 97 candidates of size 7
+-- tested 163 candidates
+signum 0  =  0
+signum x
+  | x < 0  =  -1
+  | otherwise  =  1
+
+compare :: Int -> Int -> Ordering
+-- testing 9 combinations of argument values
+-- pruning with 5/6 rules
+-- 3 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 18 candidates of size 6
+-- 0 candidates of size 7
+-- 0 candidates of size 8
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 162 candidates of size 11
+-- tested 31 candidates
+compare x y
+  | x == y  =  EQ
+  | x < y  =  LT
+  | otherwise  =  GT
+
+min :: Int -> Int -> Int -> Int
+-- testing 6 combinations of argument values
+-- pruning with 4/4 rules
+-- 3 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 36 candidates of size 6
+-- 0 candidates of size 7
+-- 0 candidates of size 8
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 2592 candidates of size 11
+-- 0 candidates of size 12
+-- 0 candidates of size 13
+-- 0 candidates of size 14
+-- 0 candidates of size 15
+-- 248400 candidates of size 16
+-- tested 49553 candidates
+min x y z  =  if x <= y
+              then if x <= z then x else z
+              else if y <= z then y else z
+
+max :: Int -> Int -> Int -> Int
+-- testing 6 combinations of argument values
+-- pruning with 4/4 rules
+-- 3 candidates of size 1
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
+-- 36 candidates of size 6
+-- 0 candidates of size 7
+-- 0 candidates of size 8
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 2592 candidates of size 11
+-- 0 candidates of size 12
+-- 0 candidates of size 13
+-- 0 candidates of size 14
+-- 0 candidates of size 15
+-- 248400 candidates of size 16
+-- tested 50103 candidates
+max x y z  =  if x <= y
+              then if y <= z then z else y
+              else if x <= z then z else x
+
diff --git a/eg/count.hs b/eg/count.hs
--- a/eg/count.hs
+++ b/eg/count.hs
@@ -38,8 +38,8 @@
   -- count x []  =  0
   -- count x (y:xs)  =  count x xs + (if x == y then 1 else 0)
   conjure "count" count'
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "==" ((==) :: A -> A -> Bool)
     , iif (undefined :: Int)
@@ -48,8 +48,8 @@
   -- a little bit larger, guards are only allowed at the root
   -- so there is a need to repeat the recursive call twice
   conjure "count" count'
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "==" ((==) :: A -> A -> Bool)
     , guard
diff --git a/eg/count.txt b/eg/count.txt
--- a/eg/count.txt
+++ b/eg/count.txt
@@ -23,7 +23,7 @@
 -- 16 candidates of size 9
 -- 20 candidates of size 10
 -- 44 candidates of size 11
--- tested 65 candidates
+-- tested 57 candidates
 count x []  =  0
 count x (y:xs)  =  (if x == y then 1 else 0) + count x xs
 
@@ -43,7 +43,7 @@
 -- 20 candidates of size 11
 -- 44 candidates of size 12
 -- 64 candidates of size 13
--- tested 127 candidates
+-- tested 155 candidates
 count x []  =  0
 count x (y:xs)
   | x == y  =  1 + count x xs
diff --git a/eg/digits.hs b/eg/digits.hs
new file mode 100644
--- /dev/null
+++ b/eg/digits.hs
@@ -0,0 +1,68 @@
+-- digits.hs: functions over digits
+--
+-- Copyright (C) 2025 Rudy Matela
+-- Distributed under the 3-Clause BSD licence (see the file LICENSE).
+import Conjure
+
+-- decimal digit sum
+digitSum :: Int -> Int
+digitSum 0  =  0
+digitSum 12  =  3
+digitSum 42  =  6
+digitSum 1337  =  14
+digitSum 31337  =  17
+
+digitCount :: Int -> Int -> Int
+digitCount 2 42  =  2
+digitCount 1 111  =  3
+digitCount 4 144  =  144
+digitCount 0 1080  =  2
+digitCount 3 1337  =  2
+digitCount 3 31337  =  3
+
+digits :: Int -> [Int]
+digits 12  =  [1,2]
+digits 42  =  [4,2]
+digits 1337  =  [1,3,3,7]
+digits 31337  =  [3,1,3,3,7]
+
+main :: IO ()
+main  =  do
+  conjure "revdigits" (reverse . digits)
+    [ con ([] :: [Int])
+    , fun ":" ((:) :: Int -> [Int] -> [Int])
+    , fun "`div`" (div :: Int -> Int -> Int)
+    , fun "`mod`" (mod :: Int -> Int -> Int)
+    , con (0 :: Int)
+    , con (10 :: Int)
+    ]
+
+  conjure "digits" digits
+    [ con ([] :: [Int])
+    , fun ":" ((:) :: Int -> [Int] -> [Int])
+    , fun "++" ((++) :: [Int] -> [Int] -> [Int])
+    , fun "`div`" (div :: Int -> Int -> Int)
+    , fun "`mod`" (mod :: Int -> Int -> Int)
+    , con (0 :: Int)
+    , con (10 :: Int)
+    ]
+
+  conjure "digitSum" digitSum
+    [ con (0 :: Int)
+    , con (10 :: Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun "`div`" (div :: Int -> Int -> Int)
+    , fun "`mod`" (mod :: Int -> Int -> Int)
+    ]
+
+  -- out-of-reach performance-wise
+  conjure "digitCount" digitCount
+    [ con (0 :: Int)
+    , con (10 :: Int)
+    , fun "+" ((+) :: Int -> Int -> Int)
+    , fun "`div`" (div :: Int -> Int -> Int)
+    , fun "`mod`" (mod :: Int -> Int -> Int)
+    , fun "==" ((==) :: Int -> Int -> Bool)
+    , guard
+    , maxTests 1080
+    ]
diff --git a/eg/digits.txt b/eg/digits.txt
new file mode 100644
--- /dev/null
+++ b/eg/digits.txt
@@ -0,0 +1,64 @@
+revdigits :: Int -> [Int]
+-- testing 4 combinations of argument values
+-- pruning with 9/9 rules
+-- 1 candidates of size 1
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- 0 candidates of size 4
+-- 24 candidates of size 5
+-- 0 candidates of size 6
+-- 287 candidates of size 7
+-- 0 candidates of size 8
+-- 4180 candidates of size 9
+-- tested 4481 candidates
+revdigits 0  =  []
+revdigits x  =  x `mod` 10:revdigits (x `div` 10)
+
+digits :: Int -> [Int]
+-- testing 4 combinations of argument values
+-- pruning with 13/13 rules
+-- 1 candidates of size 1
+-- 0 candidates of size 2
+-- 3 candidates of size 3
+-- 0 candidates of size 4
+-- 24 candidates of size 5
+-- 0 candidates of size 6
+-- 287 candidates of size 7
+-- 0 candidates of size 8
+-- 4186 candidates of size 9
+-- 18 candidates of size 10
+-- 67104 candidates of size 11
+-- tested 71513 candidates
+digits 0  =  []
+digits x  =  digits (x `div` 10) ++ [x `mod` 10]
+
+digitSum :: Int -> Int
+-- testing 5 combinations of argument values
+-- pruning with 18/22 rules
+-- 3 candidates of size 1
+-- 0 candidates of size 2
+-- 12 candidates of size 3
+-- 0 candidates of size 4
+-- 165 candidates of size 5
+-- 0 candidates of size 6
+-- 2680 candidates of size 7
+-- 84 candidates of size 8
+-- 46993 candidates of size 9
+-- tested 49164 candidates
+digitSum 0  =  0
+digitSum x  =  x `mod` 10 + digitSum (x `div` 10)
+
+digitCount :: Int -> Int -> Int
+-- testing 3 combinations of argument values
+-- pruning with 20/26 rules
+-- reasoning produced 15 incorrect properties, please re-run with more tests for faster results
+-- 4 candidates of size 1
+-- 0 candidates of size 2
+-- 29 candidates of size 3
+-- 0 candidates of size 4
+-- 545 candidates of size 5
+-- 156 candidates of size 6
+-- 12715 candidates of size 7
+-- tested 13449 candidates
+digitCount  =  undefined  -- search exhausted
+
diff --git a/eg/dupos.hs b/eg/dupos.hs
--- a/eg/dupos.hs
+++ b/eg/dupos.hs
@@ -52,7 +52,7 @@
   --                       else duplicates xs                              -- 17
   -- within reach performance wise.
   conjure "duplicates" duplicates'
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun "not" not
     , fun "&&" (&&)
     , fun ":" ((:) :: Int -> [Int] -> [Int])
@@ -61,7 +61,7 @@
     ]
 
   conjureFromSpec "duplicates" duplicatesSpec
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun "not" not
     , fun "&&" (&&)
     , fun ":" ((:) :: Int -> [Int] -> [Int])
@@ -70,8 +70,8 @@
     ]
 
   conjure "positionsFrom" positionsFrom'
-    [ unfun ([] :: [Int])
-    , unfun (1 :: Int)
+    [ con ([] :: [Int])
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "==" ((==) :: A -> A -> Bool)
diff --git a/eg/dupos.txt b/eg/dupos.txt
--- a/eg/dupos.txt
+++ b/eg/dupos.txt
@@ -5,20 +5,20 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 0 candidates of size 4
--- 1 candidates of size 5
+-- 0 candidates of size 5
 -- 0 candidates of size 6
--- 1 candidates of size 7
--- 6 candidates of size 8
--- 5 candidates of size 9
--- 16 candidates of size 10
--- 11 candidates of size 11
--- 26 candidates of size 12
--- 23 candidates of size 13
+-- 0 candidates of size 7
+-- 2 candidates of size 8
+-- 4 candidates of size 9
+-- 8 candidates of size 10
+-- 8 candidates of size 11
+-- 14 candidates of size 12
+-- 22 candidates of size 13
 -- 52 candidates of size 14
--- 49 candidates of size 15
--- 78 candidates of size 16
--- 75 candidates of size 17
--- tested 271 candidates
+-- 74 candidates of size 15
+-- 120 candidates of size 16
+-- 156 candidates of size 17
+-- tested 461 candidates
 duplicates []  =  []
 duplicates (x:xs)
   | elem x xs && not (elem x (duplicates xs))  =  x:duplicates xs
@@ -37,13 +37,13 @@
 -- 13 candidates of size 9
 -- 18 candidates of size 10
 -- 21 candidates of size 11
--- 28 candidates of size 12
--- 39 candidates of size 13
--- 54 candidates of size 14
--- 67 candidates of size 15
--- 80 candidates of size 16
--- 99 candidates of size 17
--- tested 340 candidates
+-- 32 candidates of size 12
+-- 57 candidates of size 13
+-- 102 candidates of size 14
+-- 159 candidates of size 15
+-- 228 candidates of size 16
+-- 331 candidates of size 17
+-- tested 979 candidates
 duplicates []  =  []
 duplicates (x:xs)
   | elem x xs && not (elem x (duplicates xs))  =  x:duplicates xs
@@ -58,13 +58,13 @@
 -- 0 candidates of size 4
 -- 7 candidates of size 5
 -- 0 candidates of size 6
--- 34 candidates of size 7
+-- 26 candidates of size 7
 -- 0 candidates of size 8
--- 133 candidates of size 9
--- 8 candidates of size 10
--- 510 candidates of size 11
--- 40 candidates of size 12
--- 1943 candidates of size 13
--- tested 2678 candidates
+-- 97 candidates of size 9
+-- 0 candidates of size 10
+-- 362 candidates of size 11
+-- 0 candidates of size 12
+-- 1363 candidates of size 13
+-- tested 1858 candidates
 positionsFrom  =  undefined  -- search exhausted
 
diff --git a/eg/either.hs b/eg/either.hs
--- a/eg/either.hs
+++ b/eg/either.hs
@@ -59,9 +59,9 @@
   [ fun "Left"  (Left :: A -> Either A A)
   , fun "Right" (Right :: A -> Either A A)
 
-  , unfun False
-  , unfun True
+  , con False
+  , con True
 
-  , unfun ([] :: [A])
+  , con ([] :: [A])
   , fun ":" ((:) :: A -> [A] -> [A])
   ]
diff --git a/eg/factorial.hs b/eg/factorial.hs
--- a/eg/factorial.hs
+++ b/eg/factorial.hs
@@ -15,8 +15,8 @@
 main  =  do
   -- explicit recursion
   conjure "factorial n" factorial
-    [ unfun (0::Int)
-    , unfun (1::Int)
+    [ con (0::Int)
+    , con (1::Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
@@ -27,8 +27,8 @@
 
   -- using foldr and enumFromTo
   conjure "factorial n" factorial
-    [ unfun (0::Int)
-    , unfun (1::Int)
+    [ con (0::Int)
+    , con (1::Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
diff --git a/eg/factorial.txt b/eg/factorial.txt
--- a/eg/factorial.txt
+++ b/eg/factorial.txt
@@ -2,13 +2,13 @@
 -- testing 4 combinations of argument values
 -- pruning with 27/65 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 7 candidates of size 3
--- 8 candidates of size 4
--- 28 candidates of size 5
--- 35 candidates of size 6
--- 167 candidates of size 7
--- tested 95 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 23 candidates of size 5
+-- 0 candidates of size 6
+-- 147 candidates of size 7
+-- tested 173 candidates
 factorial 0  =  1
 factorial x  =  x * factorial (x - 1)
 
@@ -16,11 +16,11 @@
 -- testing 4 combinations of argument values
 -- pruning with 32/72 rules
 -- 3 candidates of size 1
--- 3 candidates of size 2
--- 7 candidates of size 3
--- 8 candidates of size 4
--- 28 candidates of size 5
--- 75 candidates of size 6
--- tested 74 candidates
+-- 0 candidates of size 2
+-- 6 candidates of size 3
+-- 0 candidates of size 4
+-- 23 candidates of size 5
+-- 40 candidates of size 6
+-- tested 57 candidates
 factorial x  =  foldr (*) 1 [1..x]
 
diff --git a/eg/fib01.hs b/eg/fib01.hs
--- a/eg/fib01.hs
+++ b/eg/fib01.hs
@@ -31,7 +31,7 @@
   -- Found!  It takes about 12 seconds to run with maxSize=8
   -- running with maxSize = 5 for faster runtime
   conjure "fib01" fib01
-    [ unfun (0::Int)
+    [ con (0::Int)
     , fun "dec" (subtract 1 :: Int -> Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , maxSize 5
@@ -41,7 +41,7 @@
   -- It takes about 27 seconds to run with maxSize=12
   -- running with maxSize = 9 for faster runtime
   conjure "fib01" fib01
-    [ unfun (0::Int)
+    [ con (0::Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "dec" (subtract 1 :: Int -> Int)
     , fun "<=" ((<=) :: Int -> Int -> Bool)
diff --git a/eg/fib01.txt b/eg/fib01.txt
--- a/eg/fib01.txt
+++ b/eg/fib01.txt
@@ -2,11 +2,11 @@
 -- testing 8 combinations of argument values
 -- pruning with 6/10 rules
 -- 4 candidates of size 1
--- 14 candidates of size 2
--- 38 candidates of size 3
--- 111 candidates of size 4
--- 255 candidates of size 5
--- tested 422 candidates
+-- 3 candidates of size 2
+-- 9 candidates of size 3
+-- 9 candidates of size 4
+-- 27 candidates of size 5
+-- tested 52 candidates
 fib01  =  undefined  -- search exhausted
 
 fib01 :: Int -> Int -> Int -> Int
diff --git a/eg/fibonacci.hs b/eg/fibonacci.hs
--- a/eg/fibonacci.hs
+++ b/eg/fibonacci.hs
@@ -16,9 +16,9 @@
 main :: IO ()
 main  =  do
   conjure "fibonacci n" fibonacci
-    [ unfun (0::Int)
-    , unfun (1::Int)
-    , unfun (2::Int)
+    [ con (0::Int)
+    , con (1::Int)
+    , con (2::Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
diff --git a/eg/fibonacci.txt b/eg/fibonacci.txt
--- a/eg/fibonacci.txt
+++ b/eg/fibonacci.txt
@@ -2,18 +2,18 @@
 -- testing 7 combinations of argument values
 -- pruning with 21/44 rules
 -- 4 candidates of size 1
--- 3 candidates of size 2
--- 9 candidates of size 3
--- 9 candidates of size 4
--- 26 candidates of size 5
--- 27 candidates of size 6
--- 116 candidates of size 7
--- 120 candidates of size 8
--- 552 candidates of size 9
--- 538 candidates of size 10
--- 2661 candidates of size 11
--- 2661 candidates of size 12
--- tested 4133 candidates
+-- 0 candidates of size 2
+-- 7 candidates of size 3
+-- 0 candidates of size 4
+-- 18 candidates of size 5
+-- 0 candidates of size 6
+-- 94 candidates of size 7
+-- 20 candidates of size 8
+-- 466 candidates of size 9
+-- 92 candidates of size 10
+-- 2298 candidates of size 11
+-- 542 candidates of size 12
+-- tested 3531 candidates
 fibonacci 0  =  1
 fibonacci 1  =  1
 fibonacci x  =  fibonacci (x - 1) + fibonacci (x - 2)
diff --git a/eg/gcd.hs b/eg/gcd.hs
--- a/eg/gcd.hs
+++ b/eg/gcd.hs
@@ -19,7 +19,7 @@
 
 main :: IO ()
 main = conjure "gcd a b" gcd'
-  [ unfun (0::Int)
+  [ con (0::Int)
   , fun "`mod`" (mod :: Int -> Int -> Int)
   ]
   -- desired function:
diff --git a/eg/gcd.txt b/eg/gcd.txt
--- a/eg/gcd.txt
+++ b/eg/gcd.txt
@@ -2,12 +2,12 @@
 -- testing 11 combinations of argument values
 -- pruning with 0/0 rules
 -- 3 candidates of size 1
--- 6 candidates of size 2
--- 11 candidates of size 3
--- 50 candidates of size 4
--- 98 candidates of size 5
--- 330 candidates of size 6
--- tested 172 candidates
+-- 0 candidates of size 2
+-- 8 candidates of size 3
+-- 0 candidates of size 4
+-- 48 candidates of size 5
+-- 28 candidates of size 6
+-- tested 63 candidates
 gcd x 0  =  x
 gcd x y  =  gcd y (x `mod` y)
 
diff --git a/eg/higher.hs b/eg/higher.hs
--- a/eg/higher.hs
+++ b/eg/higher.hs
@@ -59,7 +59,7 @@
 
 ingredients :: [Ingredient]
 ingredients  =
-  [ unfun ([] :: [Int])
+  [ con ([] :: [Int])
   , fun ":" ((:) :: Int -> [Int] -> [Int])
   , guard
   ]
diff --git a/eg/higher.txt b/eg/higher.txt
--- a/eg/higher.txt
+++ b/eg/higher.txt
@@ -30,7 +30,7 @@
 -- 2 candidates of size 5
 -- 5 candidates of size 6
 -- 7 candidates of size 7
--- tested 13 candidates
+-- tested 19 candidates
 map f []  =  []
 map f (x:xs)  =  f x:map f xs
 
@@ -43,9 +43,9 @@
 -- 4 candidates of size 5
 -- 23 candidates of size 6
 -- 19 candidates of size 7
--- tested 38 candidates
+-- tested 43 candidates
 fold f x []  =  x
-fold f x (y:xs)  =  fold f (f x y) xs
+fold f x (y:xs)  =  f x (fold f y xs)
 
 filter :: (Int -> Bool) -> [Int] -> [Int]
 -- pruning with 3/3 rules
@@ -58,10 +58,10 @@
 -- 0 candidates of size 7
 -- 15 candidates of size 8
 -- 0 candidates of size 9
--- 21 candidates of size 10
+-- 25 candidates of size 10
 -- 0 candidates of size 11
--- 33 candidates of size 12
--- tested 47 candidates
+-- 63 candidates of size 12
+-- tested 113 candidates
 filter f []  =  []
 filter f (x:xs)
   | f x  =  x:filter f xs
diff --git a/eg/ints.hs b/eg/ints.hs
--- a/eg/ints.hs
+++ b/eg/ints.hs
@@ -39,15 +39,15 @@
     ]
 
   conjure "sum" sum
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     ]
 
   conjure "product" product
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     ]
@@ -57,8 +57,8 @@
 
 ingredients :: [Ingredient]
 ingredients =
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
+  [ con (0 :: Int)
+  , con (1 :: Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
   ]
diff --git a/eg/list.hs b/eg/list.hs
--- a/eg/list.hs
+++ b/eg/list.hs
@@ -56,30 +56,30 @@
 main :: IO ()
 main = do
   conjure "length" length'
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     ]
 
   conjure "reverse" reverse'
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   conjure "++" (+++)
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     ]
 
   conjure "++" (+++)
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "foldr" (foldr :: (Int -> [Int] -> [Int]) -> [Int] -> [Int] -> [Int])
     ]
 
   conjure "last" last'
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "null" (null :: [Int] -> Bool)
     , guard
@@ -87,26 +87,26 @@
     ]
 
   conjure "last" last'
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "undefined" (undefined :: Int)
     , maxPatternDepth 2
     ]
 
   conjure "zip" (zip')
-    [ unfun ([] :: [(Int,Int)])
+    [ con ([] :: [(Int,Int)])
     , fun ":" ((:) :: (Int,Int) -> [(Int,Int)] -> [(Int,Int)])
     , fun "," ((,) :: Int -> Int -> (Int,Int))
     ]
 
   conjure "\\/" (\/)
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     ]
 
   conjure "ordered" ordered'
-    [ unfun False
-    , unfun True
+    [ con False
+    , con True
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "<=" ((<=) :: Int -> Int -> Bool)
diff --git a/eg/list.txt b/eg/list.txt
--- a/eg/list.txt
+++ b/eg/list.txt
@@ -17,10 +17,10 @@
 -- 0 candidates of size 2
 -- 1 candidates of size 3
 -- 0 candidates of size 4
--- 4 candidates of size 5
+-- 2 candidates of size 5
 -- 1 candidates of size 6
--- 10 candidates of size 7
--- tested 16 candidates
+-- 4 candidates of size 7
+-- tested 9 candidates
 reverse []  =  []
 reverse (x:xs)  =  reverse xs ++ [x]
 
@@ -32,8 +32,8 @@
 -- 0 candidates of size 3
 -- 10 candidates of size 4
 -- 25 candidates of size 5
--- 34 candidates of size 6
--- tested 56 candidates
+-- 24 candidates of size 6
+-- tested 40 candidates
 [] ++ xs  =  xs
 (x:xs) ++ ys  =  x:(xs ++ ys)
 
@@ -44,7 +44,7 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 14 candidates of size 4
--- tested 16 candidates
+-- tested 6 candidates
 xs ++ ys  =  foldr (:) ys xs
 
 last :: [Int] -> Int
@@ -72,7 +72,7 @@
 -- 1 candidates of size 4
 -- 2 candidates of size 5
 -- 2 candidates of size 6
--- tested 5 candidates
+-- tested 6 candidates
 last []  =  undefined
 last [x]  =  x
 last (x:y:xs)  =  last (y:xs)
@@ -87,9 +87,9 @@
 -- 0 candidates of size 5
 -- 0 candidates of size 6
 -- 0 candidates of size 7
--- 6 candidates of size 8
--- 23 candidates of size 9
--- tested 13 candidates
+-- 0 candidates of size 8
+-- 11 candidates of size 9
+-- tested 3 candidates
 zip [] xs  =  []
 zip (x:xs) []  =  []
 zip (x:xs) (y:ys)  =  (x,y):zip xs ys
@@ -102,8 +102,8 @@
 -- 0 candidates of size 3
 -- 10 candidates of size 4
 -- 25 candidates of size 5
--- 34 candidates of size 6
--- tested 58 candidates
+-- 24 candidates of size 6
+-- tested 42 candidates
 [] \/ xs  =  xs
 (x:xs) \/ ys  =  x:ys \/ xs
 
@@ -119,9 +119,9 @@
 -- 13 candidates of size 7
 -- 17 candidates of size 8
 -- 25 candidates of size 9
--- 65 candidates of size 10
--- 115 candidates of size 11
--- tested 172 candidates
+-- 55 candidates of size 10
+-- 103 candidates of size 11
+-- tested 168 candidates
 ordered []  =  True
 ordered (x:xs)  =  (null xs || x <= head xs) && ordered xs
 
diff --git a/eg/maybe.hs b/eg/maybe.hs
--- a/eg/maybe.hs
+++ b/eg/maybe.hs
@@ -61,13 +61,13 @@
 
 ingredients :: [Ingredient]
 ingredients  =
-  [ unfun (Nothing :: Maybe A)
+  [ con (Nothing :: Maybe A)
   , fun "Just" (Just :: A -> Maybe A)
 
-  , unfun False
-  , unfun True
+  , con False
+  , con True
 
-  , unfun ([] :: [A])
+  , con ([] :: [A])
   , fun ":" ((:) :: A -> [A] -> [A])
   ]
 
diff --git a/eg/maybe.txt b/eg/maybe.txt
--- a/eg/maybe.txt
+++ b/eg/maybe.txt
@@ -65,7 +65,7 @@
 -- 0 candidates of size 5
 -- 1 candidates of size 6
 -- 2 candidates of size 7
--- tested 3 candidates
+-- tested 4 candidates
 catMaybes []  =  []
 catMaybes (Nothing:mxs)  =  catMaybes mxs
 catMaybes (Just x:mxs)  =  x:catMaybes mxs
diff --git a/eg/oddeven.hs b/eg/oddeven.hs
--- a/eg/oddeven.hs
+++ b/eg/oddeven.hs
@@ -30,21 +30,21 @@
 
 ingredients1 :: [Ingredient]
 ingredients1 =
-  [ unfun (0::Int)
-  , unfun (1::Int)
-  , unfun (2::Int)
+  [ con (0::Int)
+  , con (1::Int)
+  , con (2::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
 
   , fun "-" ((-) :: Int -> Int -> Int)
-  , unfun False
-  , unfun True
+  , con False
+  , con True
   ]
 
 ingredients2 :: [Ingredient]
 ingredients2 =
-  [ unfun (0::Int)
-  , unfun (1::Int)
-  , unfun (2::Int)
+  [ con (0::Int)
+  , con (1::Int)
+  , con (2::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
 
   , fun "`mod`" (mod :: Int -> Int -> Int)
diff --git a/eg/oddeven.txt b/eg/oddeven.txt
--- a/eg/oddeven.txt
+++ b/eg/oddeven.txt
@@ -2,13 +2,13 @@
 -- testing 6 combinations of argument values
 -- pruning with 21/44 rules
 -- 2 candidates of size 1
--- 1 candidates of size 2
--- 1 candidates of size 3
--- 1 candidates of size 4
--- 1 candidates of size 5
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
 -- 0 candidates of size 6
 -- 2 candidates of size 7
--- tested 8 candidates
+-- tested 4 candidates
 odd 0  =  False
 odd 1  =  True
 odd x  =  odd (x - 2)
@@ -17,13 +17,13 @@
 -- testing 6 combinations of argument values
 -- pruning with 21/44 rules
 -- 2 candidates of size 1
--- 1 candidates of size 2
--- 1 candidates of size 3
--- 1 candidates of size 4
--- 1 candidates of size 5
+-- 0 candidates of size 2
+-- 0 candidates of size 3
+-- 0 candidates of size 4
+-- 0 candidates of size 5
 -- 0 candidates of size 6
 -- 2 candidates of size 7
--- tested 8 candidates
+-- tested 4 candidates
 even 0  =  True
 even 1  =  False
 even x  =  even (x - 2)
@@ -34,9 +34,9 @@
 -- 0 candidates of size 1
 -- 0 candidates of size 2
 -- 3 candidates of size 3
--- 1 candidates of size 4
--- 46 candidates of size 5
--- tested 31 candidates
+-- 0 candidates of size 4
+-- 44 candidates of size 5
+-- tested 30 candidates
 odd x  =  1 == x `mod` 2
 
 even :: Int -> Bool
@@ -45,8 +45,8 @@
 -- 0 candidates of size 1
 -- 0 candidates of size 2
 -- 3 candidates of size 3
--- 2 candidates of size 4
--- 45 candidates of size 5
--- tested 22 candidates
+-- 0 candidates of size 4
+-- 44 candidates of size 5
+-- tested 20 candidates
 even x  =  0 == x `mod` 2
 
diff --git a/eg/peano.hs b/eg/peano.hs
--- a/eg/peano.hs
+++ b/eg/peano.hs
@@ -27,13 +27,13 @@
 main :: IO ()
 main  =  do
   conjure "+" plus
-    [ unfun Z
+    [ con Z
     , fun "S" S
     ]
 
   -- use + to conjure *
   conjure "*" times
-    [ unfun Z
+    [ con Z
     , fun "S" S
     , fun "+" (let p + Z    =  p
                    p + S q  =  S p + q
diff --git a/eg/peano.txt b/eg/peano.txt
--- a/eg/peano.txt
+++ b/eg/peano.txt
@@ -6,9 +6,9 @@
 -- 3 candidates of size 3
 -- 13 candidates of size 4
 -- 19 candidates of size 5
--- tested 23 candidates
+-- tested 26 candidates
 p + Z  =  p
-p + S q  =  S p + q
+p + S q  =  S (p + q)
 
 (*) :: Peano -> Peano -> Peano
 -- testing 7 combinations of argument values
@@ -17,9 +17,9 @@
 -- 3 candidates of size 2
 -- 6 candidates of size 3
 -- 6 candidates of size 4
--- 35 candidates of size 5
--- 86 candidates of size 6
--- tested 71 candidates
+-- 25 candidates of size 5
+-- 63 candidates of size 6
+-- tested 56 candidates
 p * Z  =  Z
 p * S q  =  p + p * q
 
diff --git a/eg/pow.hs b/eg/pow.hs
--- a/eg/pow.hs
+++ b/eg/pow.hs
@@ -16,8 +16,8 @@
   -- pow x 0  =  1
   -- pow x y  =  x * pow x (y - 1)
   conjure "pow" pow
-    [ unfun (0::Int)
-    , unfun (1::Int)
+    [ con (0::Int)
+    , con (1::Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
@@ -27,8 +27,8 @@
   --             2   3  4     5  6 7   8  9    10 11 12 13 14     15     16
   -- out of reach performance wise, OOM at size 9
   conjure "pow" pow
-    [ unfun (0::Int)
-    , unfun (1::Int)
+    [ con (0::Int)
+    , con (1::Int)
 --  , fun "sq" ((\x -> x*x) :: Int -> Int) -- cheat! OOM still
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "halve" ((`div` 2) :: Int -> Int)
diff --git a/eg/pow.txt b/eg/pow.txt
--- a/eg/pow.txt
+++ b/eg/pow.txt
@@ -2,14 +2,14 @@
 -- testing 5 combinations of argument values
 -- pruning with 14/30 rules
 -- 4 candidates of size 1
--- 11 candidates of size 2
--- 31 candidates of size 3
--- 92 candidates of size 4
--- 244 candidates of size 5
--- 730 candidates of size 6
--- 2221 candidates of size 7
--- 6950 candidates of size 8
--- tested 3356 candidates
+-- 0 candidates of size 2
+-- 11 candidates of size 3
+-- 0 candidates of size 4
+-- 78 candidates of size 5
+-- 9 candidates of size 6
+-- 809 candidates of size 7
+-- 557 candidates of size 8
+-- tested 912 candidates
 pow x 0  =  1
 pow x y  =  x * pow x (y - 1)
 
@@ -17,11 +17,11 @@
 -- testing 5 combinations of argument values
 -- pruning with 15/19 rules
 -- 4 candidates of size 1
--- 13 candidates of size 2
--- 40 candidates of size 3
--- 103 candidates of size 4
--- 259 candidates of size 5
--- 750 candidates of size 6
--- tested 1169 candidates
+-- 2 candidates of size 2
+-- 5 candidates of size 3
+-- 9 candidates of size 4
+-- 31 candidates of size 5
+-- 178 candidates of size 6
+-- tested 229 candidates
 pow  =  undefined  -- search exhausted
 
diff --git a/eg/replicate.hs b/eg/replicate.hs
--- a/eg/replicate.hs
+++ b/eg/replicate.hs
@@ -26,10 +26,10 @@
 main :: IO ()
 main = do
   conjure "replicate" replicate'
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "-" ((-) :: Int -> Int -> Int)
-    , unfun ""
+    , con ""
     , fun ":" ((:) :: Char -> String -> String)
     ]
 
@@ -49,7 +49,7 @@
 
   -- alternative generation using recursion
   conjure "replicates" replicates'
-    [ unfun ""
+    [ con ""
     , fun ":" ((:) :: Char -> String -> String)
     , fun "++" ((++) :: String -> String -> String)
     , fun "replicate" (replicate :: Int -> Char -> String)
diff --git a/eg/replicate.txt b/eg/replicate.txt
--- a/eg/replicate.txt
+++ b/eg/replicate.txt
@@ -4,12 +4,12 @@
 -- 1 candidates of size 1
 -- 0 candidates of size 2
 -- 1 candidates of size 3
--- 1 candidates of size 4
--- 2 candidates of size 5
--- 1 candidates of size 6
+-- 0 candidates of size 4
+-- 1 candidates of size 5
+-- 0 candidates of size 6
 -- 1 candidates of size 7
--- 2 candidates of size 8
--- tested 8 candidates
+-- 1 candidates of size 8
+-- tested 5 candidates
 replicate 0 c  =  ""
 replicate x c  =  c:replicate (x - 1) c
 
@@ -43,10 +43,10 @@
 -- 1 candidates of size 3
 -- 0 candidates of size 4
 -- 1 candidates of size 5
--- 3 candidates of size 6
+-- 2 candidates of size 6
 -- 1 candidates of size 7
--- 12 candidates of size 8
--- tested 10 candidates
+-- 8 candidates of size 8
+-- tested 14 candidates
 replicates "" x  =  ""
 replicates (c:cs) x  =  replicate x c ++ replicates cs x
 
diff --git a/eg/setelem.hs b/eg/setelem.hs
--- a/eg/setelem.hs
+++ b/eg/setelem.hs
@@ -19,8 +19,8 @@
 main :: IO ()
 main = do
   conjure "elem" (elem')
-    [ unfun True
-    , unfun False
+    [ con True
+    , con False
     , fun "||" (||)
     , fun "&&" (&&)
     , fun "not" not
@@ -28,8 +28,8 @@
     ]
 
   conjure "set" (set')
-    [ unfun True
-    , unfun False
+    [ con True
+    , con False
     , fun "||" (||)
     , fun "&&" (&&)
     , fun "not" not
diff --git a/eg/setelem.txt b/eg/setelem.txt
--- a/eg/setelem.txt
+++ b/eg/setelem.txt
@@ -9,7 +9,7 @@
 -- 0 candidates of size 6
 -- 0 candidates of size 7
 -- 16 candidates of size 8
--- tested 19 candidates
+-- tested 11 candidates
 elem x []  =  False
 elem x (y:xs)  =  x == y || elem x xs
 
diff --git a/eg/sort.hs b/eg/sort.hs
--- a/eg/sort.hs
+++ b/eg/sort.hs
@@ -3,21 +3,18 @@
 -- Copyright (C) 2021-2025 Rudy Matela
 -- Distributed under the 3-Clause BSD licence (see the file LICENSE).
 import Conjure
-import Data.List (insert, sort)
+import Data.List (insert)
 
 sort' :: [Int] -> [Int]
 sort' []       =  []
-sort' [x]      =  [x]
-sort' [x,y]
-  | x <= y     =  [x,y]
-  | otherwise  =  [y,x]
-sort' [x,y,z]
-  | x <= y && y <= z  =  [x,y,z]
-  | x <= z && z <= y  =  [x,z,y]
-  | y <= x && x <= z  =  [y,x,z]
-  | y <= z && z <= x  =  [y,z,x]
-  | z <= x && x <= y  =  [z,x,y]
-  | z <= y && y <= x  =  [z,y,x]
+sort' [0]      =  [0]
+sort' [1]      =  [1]
+sort' [0,2]    =  [0,2]
+sort' [1,0]    =  [0,1]
+sort' [0,1,2]  =  [0,1,2]
+sort' [2,1,0]  =  [0,1,2]
+sort' [1,0,1]  =  [0,1,1]
+sort' [0,1,0,1]  =  [0,0,1,1]
 
 insert' :: Int -> [Int] -> [Int]
 insert' 0 []  =  [0]
@@ -25,99 +22,71 @@
 insert' 1 [0,2]  =  [0,1,2]
 insert' 2 [0,1]  =  [0,1,2]
 
--- merge' :: [Int] -> [Int] -> [Int]
--- merge' xs ys  =  sort (xs ++ ys)
-
 merge' :: [Int] -> [Int] -> [Int]
 merge' [] []  =  []
-merge' xs []  =  xs
-merge' [] ys  =  ys
-merge' [x] [y] | x <= y     =  [x,y]
-               | otherwise  =  [y,x]
+merge' [0] []  =  [0]
+merge' [] [0]  =  [0]
+merge' [0] [1]  =  [0,1]
+merge' [1] [0]  =  [0,1]
+merge' [1] [0,2]  =  [0,1,2]
+merge' [0,2] [1]  =  [0,1,2]
+merge' [2] [0,1]  =  [0,1,2]
 merge' [0,1] [0,1]  =  [0,0,1,1]
 merge' [0,1] [2,3]  =  [0,1,2,3]
 merge' [0,2] [1,3]  =  [0,1,2,3]
 merge' [0,1] [1,2]  =  [0,1,1,2]
 merge' [1,2] [0,1]  =  [0,1,1,2]
-merge' [0,2] [1,1]  =  [0,1,1,2]
 
 main :: IO ()
 main = do
-  -- recursive insertion sort
-  -- sort []  =  []
-  -- sort (x:xs)  =  insert x (sort xs)
-  conjure "sort" sort'
-    [ unfun ([] :: [Int])
-    , fun "insert" (insert :: Int -> [Int] -> [Int])
-    , fun "head" (head :: [Int] -> Int)
-    , fun "tail" (tail :: [Int] -> [Int])
-    , fun "null" (null :: [Int] -> Bool)
-    ]
-
-  -- now through fold
-  -- sort xs  =  foldr insert [] xs
-  conjure "sort" sort'
-    [ unfun ([] :: [Int])
-    , fun "insert" (insert :: Int -> [Int] -> [Int])
-    , fun "foldr" (foldr :: (Int -> [Int] -> [Int]) -> [Int] -> [Int] -> [Int])
-    ]
-
   -- an insert function
   conjure "insert" insert'
     [ fun "[]" ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "<=" ((<=) :: Int -> Int -> Bool)
     , guard
-    , target 50400
     ]
 
-  -- qsort []  =  []                           -- 1
-  -- qsort (x:xs)  =  qsort (filter (x >) xs)  -- 6
-  --            ++ (x:qsort (filter (x <=) xs) -- 14
-  -- this one is not out of reach performance wise,
-  -- but is not generated because of the deconstruction restriction.
-  -- The following does generate a correct but inneficient version of qsort.
-  conjure "qsort" sort'
-    [ unfun ([] :: [Int])
-    , fun ":" ((:) :: Int -> [Int] -> [Int])
-    , fun "++" ((++) :: [Int] -> [Int] -> [Int])
-    , fun "<=" ((<=) :: Int -> Int -> Bool)
-    , fun ">"  ((>)  :: Int -> Int -> Bool)
-    , fun "filter" (filter :: (Int -> Bool) -> [Int] -> [Int])
+  -- recursive insertion sort
+  conjure "sort" sort'
+    [ con ([] :: [Int])
+    , fun "insert" (insert :: Int -> [Int] -> [Int])
     ]
 
-  -- if we disable the descent requirement, we get the efficient qsort
-  -- though with a larger search space
-  conjure "qsort" sort'
-    [ unfun ([] :: [Int])
-    , fun ":" ((:) :: Int -> [Int] -> [Int])
-    , fun "++" ((++) :: [Int] -> [Int] -> [Int])
-    , fun "<=" ((<=) :: Int -> Int -> Bool)
-    , fun ">"  ((>)  :: Int -> Int -> Bool)
-    , fun "filter" (filter :: (Int -> Bool) -> [Int] -> [Int])
-    , dontRequireDescent
+  -- folding insertion sort
+  conjure "sort" sort'
+    [ con ([] :: [Int])
+    , fun "insert" (insert :: Int -> [Int] -> [Int])
+    , fun "foldr" (foldr :: (Int -> [Int] -> [Int]) -> [Int] -> [Int] -> [Int])
     ]
 
-  -- found!  candidate #1703311 @ size 22
+  -- found!  candidate #309279 @ size 22 after ~11s
   -- merge [] xs  =  xs
   -- merge (x:xs) []  =  x:xs
   -- merge (x:xs) (y:ys)
   --   | x <= y  =  x:merge xs (y:ys)
-  --   | otherwise  =  merge (y:x:xs) ys
-  -- set target to 2 000 000 to reach it
+  --   | otherwise  =  y:merge ys (x:xs)
+  -- set target to 360 000 to reach it
   conjure "merge" merge'
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "<=" ((<=) :: Int -> Int -> Bool)
     , guard
     , maxTests 1080
-    , target 10080 -- set to 2 000 000 to reach solution
+    , target 3600  -- set to 360 000 to reach solution
     ]
 
-  -- unreachable: needs about 26, but can only reach 16
-  conjure "merge" merge'
-    [ fun ":" ((:) :: Int -> [Int] -> [Int])
-    , fun "compare" (compare :: Int -> Int -> Ordering)
-    , ordcase (undefined :: [Int])
-    , target 1080
+  -- Produces a inefficient degenerate version of qsort
+  -- where filter is applied _after_ sorting.
+  conjure "qsort" sort'
+    [ con ([] :: [Int])
+    , fun ":" ((:) :: Int -> [Int] -> [Int])
+    , fun "++" ((++) :: [Int] -> [Int] -> [Int])
+    , fun "<=" ((<=) :: Int -> Int -> Bool)
+    , fun ">"  ((>)  :: Int -> Int -> Bool)
+    , fun "filter" (filter :: (Int -> Bool) -> [Int] -> [Int])
+    -- if we disable the descent requirement and carry on,
+    -- we eventually get the efficient qsort
+    -- , dontRequireDescent
+    -- , carryOn
     ]
diff --git a/eg/sort.txt b/eg/sort.txt
--- a/eg/sort.txt
+++ b/eg/sort.txt
@@ -1,25 +1,3 @@
-sort :: [Int] -> [Int]
--- testing 360 combinations of argument values
--- pruning with 6/7 rules
--- 2 candidates of size 1
--- 2 candidates of size 2
--- 2 candidates of size 3
--- 7 candidates of size 4
--- 14 candidates of size 5
--- tested 15 candidates
-sort []  =  []
-sort (x:xs)  =  insert x (sort xs)
-
-sort :: [Int] -> [Int]
--- testing 360 combinations of argument values
--- pruning with 1/2 rules
--- 2 candidates of size 1
--- 0 candidates of size 2
--- 0 candidates of size 3
--- 2 candidates of size 4
--- tested 4 candidates
-sort  =  foldr insert []
-
 insert :: Int -> [Int] -> [Int]
 -- testing 4 combinations of argument values
 -- pruning with 4/4 rules
@@ -30,101 +8,84 @@
 -- 2 candidates of size 5
 -- 2 candidates of size 6
 -- 2 candidates of size 7
--- 4 candidates of size 8
+-- 0 candidates of size 8
 -- 2 candidates of size 9
--- 8 candidates of size 10
--- 18 candidates of size 11
--- 16 candidates of size 12
--- 70 candidates of size 13
--- 32 candidates of size 14
--- 226 candidates of size 15
--- 64 candidates of size 16
--- 602 candidates of size 17
--- tested 519 candidates
+-- 0 candidates of size 10
+-- 2 candidates of size 11
+-- 0 candidates of size 12
+-- 6 candidates of size 13
+-- 0 candidates of size 14
+-- 22 candidates of size 15
+-- 0 candidates of size 16
+-- 22 candidates of size 17
+-- tested 45 candidates
 insert x []  =  [x]
 insert x (y:xs)
-  | x <= y  =  x:insert y xs
-  | otherwise  =  y:insert x xs
+  | y <= x  =  y:insert x xs
+  | otherwise  =  x:y:xs
 
-qsort :: [Int] -> [Int]
--- testing 360 combinations of argument values
--- pruning with 8/8 rules
+sort :: [Int] -> [Int]
+-- testing 9 combinations of argument values
+-- pruning with 0/0 rules
 -- 2 candidates of size 1
 -- 0 candidates of size 2
--- 1 candidates of size 3
+-- 0 candidates of size 3
 -- 0 candidates of size 4
--- 4 candidates of size 5
--- 3 candidates of size 6
--- 10 candidates of size 7
--- 21 candidates of size 8
--- 36 candidates of size 9
--- 105 candidates of size 10
--- 182 candidates of size 11
--- 471 candidates of size 12
--- 988 candidates of size 13
--- 2183 candidates of size 14
--- tested 2437 candidates
-qsort []  =  []
-qsort (x:xs)  =  filter (x >) (qsort xs) ++ (x:filter (x <=) (qsort xs))
+-- 1 candidates of size 5
+-- tested 3 candidates
+sort []  =  []
+sort (x:xs)  =  insert x (sort xs)
 
-qsort :: [Int] -> [Int]
--- testing 360 combinations of argument values
--- pruning with 8/8 rules
+sort :: [Int] -> [Int]
+-- testing 9 combinations of argument values
+-- pruning with 1/2 rules
 -- 2 candidates of size 1
 -- 0 candidates of size 2
--- 1 candidates of size 3
--- 0 candidates of size 4
--- 4 candidates of size 5
--- 3 candidates of size 6
--- 16 candidates of size 7
--- 35 candidates of size 8
--- 80 candidates of size 9
--- 239 candidates of size 10
--- 478 candidates of size 11
--- 1325 candidates of size 12
--- 2980 candidates of size 13
--- 7159 candidates of size 14
--- tested 6564 candidates
-qsort []  =  []
-qsort (x:xs)  =  qsort (filter (x >) xs) ++ (x:qsort (filter (x <=) xs))
+-- 0 candidates of size 3
+-- 2 candidates of size 4
+-- tested 4 candidates
+sort  =  foldr insert []
 
 merge :: [Int] -> [Int] -> [Int]
--- testing 1080 combinations of argument values
+-- testing 13 combinations of argument values
 -- pruning with 4/4 rules
 -- 3 candidates of size 1
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 10 candidates of size 4
 -- 0 candidates of size 5
--- 16 candidates of size 6
--- 13 candidates of size 7
--- 22 candidates of size 8
--- 114 candidates of size 9
--- 36 candidates of size 10
--- 472 candidates of size 11
--- 568 candidates of size 12
--- 1442 candidates of size 13
--- 4204 candidates of size 14
--- 5426 candidates of size 15
--- tested 12326 candidates
+-- 6 candidates of size 6
+-- 26 candidates of size 7
+-- 6 candidates of size 8
+-- 67 candidates of size 9
+-- 38 candidates of size 10
+-- 152 candidates of size 11
+-- 158 candidates of size 12
+-- 296 candidates of size 13
+-- 718 candidates of size 14
+-- 560 candidates of size 15
+-- 3728 candidates of size 16
+-- tested 5768 candidates
 merge  =  undefined  -- search exhausted
 
-merge :: [Int] -> [Int] -> [Int]
--- testing 360 combinations of argument values
--- pruning with 1/2 rules
+qsort :: [Int] -> [Int]
+-- testing 9 combinations of argument values
+-- pruning with 8/8 rules
 -- 2 candidates of size 1
 -- 0 candidates of size 2
--- 0 candidates of size 3
--- 6 candidates of size 4
--- 0 candidates of size 5
--- 10 candidates of size 6
--- 7 candidates of size 7
--- 14 candidates of size 8
--- 41 candidates of size 9
--- 106 candidates of size 10
--- 144 candidates of size 11
--- 588 candidates of size 12
--- 958 candidates of size 13
--- tested 1876 candidates
-merge  =  undefined  -- search exhausted
+-- 1 candidates of size 3
+-- 0 candidates of size 4
+-- 2 candidates of size 5
+-- 3 candidates of size 6
+-- 4 candidates of size 7
+-- 10 candidates of size 8
+-- 18 candidates of size 9
+-- 39 candidates of size 10
+-- 87 candidates of size 11
+-- 165 candidates of size 12
+-- 409 candidates of size 13
+-- 809 candidates of size 14
+-- tested 1377 candidates
+qsort []  =  []
+qsort (x:xs)  =  filter (x >) (qsort xs) ++ (x:filter (x <=) (qsort xs))
 
diff --git a/eg/spec.hs b/eg/spec.hs
--- a/eg/spec.hs
+++ b/eg/spec.hs
@@ -15,8 +15,8 @@
 
 squareIngredients :: [Ingredient]
 squareIngredients  =
-  [ unfun (0::Int)
-  , unfun (1::Int)
+  [ con (0::Int)
+  , con (1::Int)
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
   ]
@@ -39,7 +39,7 @@
 sumIngredients :: [Ingredient]
 sumIngredients  =
   [ fun "null" (null :: [Int] -> Bool)
-  , unfun (0::Int)
+  , con (0::Int)
   , fun "+"    ((+) :: Int -> Int -> Int)
   , fun "head" (head :: [Int] -> Int)
   , fun "tail" (tail :: [Int] -> [Int])
diff --git a/eg/spec.txt b/eg/spec.txt
--- a/eg/spec.txt
+++ b/eg/spec.txt
@@ -21,7 +21,7 @@
 -- 2 candidates of size 3
 -- 3 candidates of size 4
 -- 5 candidates of size 5
--- tested 9 candidates
+-- tested 13 candidates
 sum []  =  0
 sum (x:xs)  =  x + sum xs
 
@@ -33,7 +33,7 @@
 -- 31 candidates of size 4
 -- 94 candidates of size 5
 -- 225 candidates of size 6
--- tested 212 candidates
+-- tested 286 candidates
 [] ++ xs  =  xs
 (x:xs) ++ ys  =  x:(xs ++ ys)
 
diff --git a/eg/subset.hs b/eg/subset.hs
--- a/eg/subset.hs
+++ b/eg/subset.hs
@@ -44,9 +44,9 @@
   -- subset [] ys  =  True
   -- subset (x:xs) ys  =  elem x ys && subset xs ys
   conjure "subset" (subset')
-    [ unfun ([] :: [Int])
-    , unfun True
-    , unfun False
+    [ con ([] :: [Int])
+    , con True
+    , con False
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "elem" (elem :: Int -> [Int] -> Bool)
diff --git a/eg/subset.txt b/eg/subset.txt
--- a/eg/subset.txt
+++ b/eg/subset.txt
@@ -9,7 +9,7 @@
 -- 0 candidates of size 6
 -- 6 candidates of size 7
 -- 176 candidates of size 8
--- tested 176 candidates
+-- tested 48 candidates
 subset [] xs  =  True
 subset (x:xs) ys  =  elem x ys && subset xs ys
 
diff --git a/eg/take-drop.hs b/eg/take-drop.hs
--- a/eg/take-drop.hs
+++ b/eg/take-drop.hs
@@ -27,9 +27,9 @@
   -- drop x []  =  []                   -- 2
   -- drop x (y:xs)  =  drop (x - 1) xs  -- 7
   conjure "drop" (drop' :: Int -> [A] -> [A])
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , unfun ([] :: [A])
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , con ([] :: [A])
     , fun ":" ((:) :: A -> [A] -> [A])
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
@@ -38,9 +38,9 @@
   -- take x []  =  []                     -- 2
   -- take x (y:xs)  =  y:take (x - 1) xs  -- 9
   conjure "take" (take' :: Int -> [A] -> [A])
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , unfun ([] :: [A])
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , con ([] :: [A])
     , fun "-" ((-) :: Int -> Int -> Int)
     , fun ":" ((:) :: A -> [A] -> [A])
     ]
diff --git a/eg/take-drop.txt b/eg/take-drop.txt
--- a/eg/take-drop.txt
+++ b/eg/take-drop.txt
@@ -2,13 +2,13 @@
 -- testing 360 combinations of argument values
 -- pruning with 4/7 rules
 -- 2 candidates of size 1
--- 1 candidates of size 2
+-- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 0 candidates of size 4
 -- 2 candidates of size 5
 -- 5 candidates of size 6
--- 5 candidates of size 7
--- tested 11 candidates
+-- 3 candidates of size 7
+-- tested 10 candidates
 drop 0 xs  =  xs
 drop x []  =  []
 drop x (y:xs)  =  drop (x - 1) xs
@@ -17,15 +17,15 @@
 -- testing 153 combinations of argument values
 -- pruning with 4/7 rules
 -- 2 candidates of size 1
--- 1 candidates of size 2
+-- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 0 candidates of size 4
 -- 0 candidates of size 5
--- 3 candidates of size 6
+-- 0 candidates of size 6
 -- 2 candidates of size 7
--- 6 candidates of size 8
--- 5 candidates of size 9
--- tested 15 candidates
+-- 0 candidates of size 8
+-- 3 candidates of size 9
+-- tested 5 candidates
 take 0 xs  =  []
 take x []  =  []
 take x (y:xs)  =  y:take (x - 1) xs
diff --git a/eg/tapps.hs b/eg/tapps.hs
--- a/eg/tapps.hs
+++ b/eg/tapps.hs
@@ -27,8 +27,8 @@
 
 ingredients :: [Ingredient]
 ingredients =
-  [ unfun (0 :: Int)
-  , unfun (1 :: Int)
+  [ con (0 :: Int)
+  , con (1 :: Int)
 #if __GLASGOW_HASKELL__ < 800
   , fun "+" ((+) :: Int -> Int -> Int)
   , fun "*" ((*) :: Int -> Int -> Int)
diff --git a/eg/tapps.txt b/eg/tapps.txt
--- a/eg/tapps.txt
+++ b/eg/tapps.txt
@@ -16,7 +16,7 @@
 -- 1 candidates of size 3
 -- 2 candidates of size 4
 -- 10 candidates of size 5
--- tested 12 candidates
+-- tested 16 candidates
 product []  =  1
 product (x:xs)  =  x * product xs
 
@@ -27,6 +27,6 @@
 -- 1 candidates of size 2
 -- 1 candidates of size 3
 -- 5 candidates of size 4
--- tested 8 candidates
+-- tested 9 candidates
 product  =  foldr (*) 1
 
diff --git a/eg/these.hs b/eg/these.hs
--- a/eg/these.hs
+++ b/eg/these.hs
@@ -78,12 +78,12 @@
     ]
 
   conjure "listhese" listhese'
-    [ unfun ([] :: [A])
+    [ con ([] :: [A])
     , fun ":" ((:) :: A -> [A] -> [A])
     ]
 
   conjure "cathis" cathis'
-    [ unfun ([] :: [A])
+    [ con ([] :: [A])
     , fun ":" ((:) :: A -> [A] -> [A])
     , fun "isThis" (isThis :: These A B -> Bool)
     , fun "fromThis" (fromThis :: These A B -> A)
@@ -91,7 +91,7 @@
     ]
 
   conjure "cathat" cathat'
-    [ unfun ([] :: [B])
+    [ con ([] :: [B])
     , fun ":" ((:) :: B -> [B] -> [B])
     , fun "isThat" (isThat :: These A B -> Bool)
     , fun "fromThat" (fromThat :: These A B -> B)
@@ -99,19 +99,19 @@
     ]
 
   conjure "cathis" cathis'
-    [ unfun ([] :: [A])
+    [ con ([] :: [A])
     , fun ":" ((:) :: A -> [A] -> [A])
     , maxPatternDepth 2
     ]
 
   conjure "cathat" cathat'
-    [ unfun ([] :: [B])
+    [ con ([] :: [B])
     , fun ":" ((:) :: B -> [B] -> [B])
     , maxPatternDepth 2
     ]
 
   conjure "cathese" cathese'
-    [ unfun ([] :: [A])
+    [ con ([] :: [A])
     , fun ":" ((:) :: A -> [A] -> [A])
     , maxPatternDepth 2
     ]
diff --git a/eg/these.txt b/eg/these.txt
--- a/eg/these.txt
+++ b/eg/these.txt
@@ -44,13 +44,13 @@
 -- 0 candidates of size 3
 -- 0 candidates of size 4
 -- 0 candidates of size 5
--- 1 candidates of size 6
--- 2 candidates of size 7
+-- 0 candidates of size 6
+-- 0 candidates of size 7
 -- 0 candidates of size 8
--- 1 candidates of size 9
--- 4 candidates of size 10
--- 2 candidates of size 11
--- tested 10 candidates
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 1 candidates of size 11
+-- tested 2 candidates
 cathis []  =  []
 cathis (t:ts)
   | isThis t  =  fromThis t:cathis ts
@@ -64,13 +64,13 @@
 -- 0 candidates of size 3
 -- 0 candidates of size 4
 -- 0 candidates of size 5
--- 1 candidates of size 6
--- 2 candidates of size 7
+-- 0 candidates of size 6
+-- 0 candidates of size 7
 -- 0 candidates of size 8
--- 1 candidates of size 9
--- 4 candidates of size 10
--- 2 candidates of size 11
--- tested 10 candidates
+-- 0 candidates of size 9
+-- 0 candidates of size 10
+-- 1 candidates of size 11
+-- tested 2 candidates
 cathat []  =  []
 cathat (t:ts)
   | isThat t  =  fromThat t:cathat ts
@@ -88,9 +88,9 @@
 -- 0 candidates of size 7
 -- 2 candidates of size 8
 -- 6 candidates of size 9
--- 7 candidates of size 10
--- 13 candidates of size 11
--- tested 18 candidates
+-- 5 candidates of size 10
+-- 9 candidates of size 11
+-- tested 23 candidates
 cathis []  =  []
 cathis (Neither:ts)  =  cathis ts
 cathis (This x:ts)  =  x:cathis ts
@@ -110,8 +110,8 @@
 -- 0 candidates of size 8
 -- 2 candidates of size 9
 -- 4 candidates of size 10
--- 3 candidates of size 11
--- tested 9 candidates
+-- 1 candidates of size 11
+-- tested 8 candidates
 cathat []  =  []
 cathat (Neither:ts)  =  cathat ts
 cathat (This x:ts)  =  cathat ts
@@ -129,14 +129,14 @@
 -- 0 candidates of size 6
 -- 0 candidates of size 7
 -- 0 candidates of size 8
--- 4 candidates of size 9
--- 8 candidates of size 10
--- 11 candidates of size 11
--- 38 candidates of size 12
--- 26 candidates of size 13
--- 140 candidates of size 14
--- 57 candidates of size 15
--- tested 269 candidates
+-- 3 candidates of size 9
+-- 7 candidates of size 10
+-- 4 candidates of size 11
+-- 27 candidates of size 12
+-- 3 candidates of size 13
+-- 78 candidates of size 14
+-- 1 candidates of size 15
+-- tested 124 candidates
 cathese []  =  []
 cathese (Neither:ts)  =  cathese ts
 cathese (That x:ts)  =  x:cathese ts
diff --git a/eg/tree.hs b/eg/tree.hs
--- a/eg/tree.hs
+++ b/eg/tree.hs
@@ -109,31 +109,31 @@
     ]
 
   conjure "size" size
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "nil" nil
     ]
 
   conjure "height" height
-    [ unfun (0 :: Int)
-    , unfun (1 :: Int)
-    , unfun (-1 :: Int)
+    [ con (0 :: Int)
+    , con (1 :: Int)
+    , con (-1 :: Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "max" (max :: Int -> Int -> Int)
     , fun "nil" nil
     ]
 
   conjure "mem" mem
-    [ unfun False
+    [ con False
     , fun "||" (||)
     , fun "==" ((==) :: Int -> Int -> Bool)
     ]
 
   -- unreachable: needs size 22 but OOMs at 19/20 (v0.5.16)
   conjure "ordered" ordered
-    [ unfun True
-    , unfun False
+    [ con True
+    , con False
     , fun "&&" (&&)
     , fun "||" (||)
     , fun "<" ((<) :: Int -> Int -> Bool)
@@ -149,19 +149,19 @@
     ]
 
   conjure "preorder" preorder
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   conjure "inorder" inorder
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
 
   conjure "posorder" posorder
-    [ unfun ([] :: [Int])
+    [ con ([] :: [Int])
     , fun ":" ((:) :: Int -> [Int] -> [Int])
     , fun "++" ((++) :: [Int] -> [Int] -> [Int])
     ]
diff --git a/eg/tree.txt b/eg/tree.txt
--- a/eg/tree.txt
+++ b/eg/tree.txt
@@ -75,7 +75,7 @@
 -- 0 candidates of size 10
 -- 0 candidates of size 11
 -- 36 candidates of size 12
--- tested 42 candidates
+-- tested 18 candidates
 mem x Leaf  =  False
 mem x (Node t1 y t2)  =  mem x t1 || (x == y || mem x t2)
 
@@ -90,11 +90,11 @@
 -- 12 candidates of size 6
 -- 0 candidates of size 7
 -- 36 candidates of size 8
--- 104 candidates of size 9
+-- 72 candidates of size 9
 -- 0 candidates of size 10
--- 418 candidates of size 11
--- 1064 candidates of size 12
--- tested 1639 candidates
+-- 290 candidates of size 11
+-- 712 candidates of size 12
+-- tested 1127 candidates
 ordered  =  undefined  -- search exhausted
 
 ordered :: Tree -> Bool
@@ -115,9 +115,9 @@
 -- 0 candidates of size 4
 -- 2 candidates of size 5
 -- 4 candidates of size 6
--- 4 candidates of size 7
+-- 2 candidates of size 7
 -- 8 candidates of size 8
--- tested 13 candidates
+-- tested 11 candidates
 preorder Leaf  =  []
 preorder (Node t1 x t2)  =  x:(preorder t1 ++ preorder t2)
 
@@ -128,11 +128,11 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 0 candidates of size 4
--- 2 candidates of size 5
+-- 0 candidates of size 5
 -- 4 candidates of size 6
--- 4 candidates of size 7
--- 8 candidates of size 8
--- tested 17 candidates
+-- 2 candidates of size 7
+-- 4 candidates of size 8
+-- tested 9 candidates
 inorder Leaf  =  []
 inorder (Node t1 x t2)  =  inorder t1 ++ (x:inorder t2)
 
@@ -143,13 +143,13 @@
 -- 0 candidates of size 2
 -- 0 candidates of size 3
 -- 0 candidates of size 4
--- 2 candidates of size 5
+-- 0 candidates of size 5
 -- 4 candidates of size 6
--- 4 candidates of size 7
--- 8 candidates of size 8
--- 14 candidates of size 9
--- 16 candidates of size 10
--- tested 47 candidates
+-- 2 candidates of size 7
+-- 4 candidates of size 8
+-- 10 candidates of size 9
+-- 8 candidates of size 10
+-- tested 27 candidates
 posorder Leaf  =  []
 posorder (Node t1 x t2)  =  posorder t1 ++ (posorder t2 ++ [x])
 
diff --git a/eg/tri.hs b/eg/tri.hs
--- a/eg/tri.hs
+++ b/eg/tri.hs
@@ -12,7 +12,7 @@
 main :: IO ()
 main  =  do
   conjure "tri" tri
-    [ unfun (1::Int)
+    [ con (1::Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
     ]
diff --git a/eg/tri.txt b/eg/tri.txt
--- a/eg/tri.txt
+++ b/eg/tri.txt
@@ -4,11 +4,11 @@
 -- 2 candidates of size 1
 -- 0 candidates of size 2
 -- 5 candidates of size 3
--- 5 candidates of size 4
+-- 0 candidates of size 4
 -- 10 candidates of size 5
--- 8 candidates of size 6
+-- 0 candidates of size 6
 -- 41 candidates of size 7
--- tested 31 candidates
+-- tested 53 candidates
 tri 1  =  1
 tri x  =  x + tri (x - 1)
 
diff --git a/eg/tuple.txt b/eg/tuple.txt
--- a/eg/tuple.txt
+++ b/eg/tuple.txt
@@ -2,7 +2,7 @@
 -- testing 4 combinations of argument values
 -- pruning with 0/0 rules
 -- 0 candidates of size 1
--- 1 candidates of size 2
+-- 2 candidates of size 2
 -- tested 1 candidates
 fst (x,y)  =  x
 
@@ -10,8 +10,8 @@
 -- testing 4 combinations of argument values
 -- pruning with 0/0 rules
 -- 0 candidates of size 1
--- 1 candidates of size 2
--- tested 1 candidates
+-- 2 candidates of size 2
+-- tested 2 candidates
 snd (x,y)  =  y
 
 swap :: (A,A) -> (A,A)
@@ -20,8 +20,8 @@
 -- 1 candidates of size 1
 -- 0 candidates of size 2
 -- 0 candidates of size 3
--- 1 candidates of size 4
--- tested 2 candidates
+-- 4 candidates of size 4
+-- tested 4 candidates
 swap (x,y)  =  (y,x)
 
 curry :: ((A,A) -> A) -> A -> A -> A
@@ -51,10 +51,10 @@
 -- 0 candidates of size 4
 -- 0 candidates of size 5
 -- 0 candidates of size 6
--- 7 candidates of size 7
--- 19 candidates of size 8
--- 34 candidates of size 9
--- tested 36 candidates
+-- 5 candidates of size 7
+-- 11 candidates of size 8
+-- 17 candidates of size 9
+-- tested 32 candidates
 pairwise []  =  []
 pairwise (x:xs)  =  (x,head xs):pairwise (tail xs)
 
@@ -66,11 +66,11 @@
 -- 1 candidates of size 3
 -- 3 candidates of size 4
 -- 5 candidates of size 5
--- 11 candidates of size 6
--- 22 candidates of size 7
--- 46 candidates of size 8
--- 106 candidates of size 9
--- tested 124 candidates
+-- 9 candidates of size 6
+-- 17 candidates of size 7
+-- 35 candidates of size 8
+-- 72 candidates of size 9
+-- tested 101 candidates
 catpairs []  =  []
 catpairs (xy:xys)  =  fst xy:snd xy:catpairs xys
 
@@ -83,9 +83,9 @@
 -- 0 candidates of size 4
 -- 0 candidates of size 5
 -- 0 candidates of size 6
--- 7 candidates of size 7
--- 26 candidates of size 8
--- tested 23 candidates
+-- 5 candidates of size 7
+-- 14 candidates of size 8
+-- tested 18 candidates
 pairwise []  =  []
 pairwise [x]  =  []
 pairwise (x:y:xs)  =  (x,y):pairwise xs
@@ -98,10 +98,10 @@
 -- 1 candidates of size 3
 -- 3 candidates of size 4
 -- 6 candidates of size 5
--- 15 candidates of size 6
--- 31 candidates of size 7
--- 68 candidates of size 8
--- tested 97 candidates
+-- 12 candidates of size 6
+-- 23 candidates of size 7
+-- 48 candidates of size 8
+-- tested 82 candidates
 catpairs []  =  []
 catpairs ((x,y):xys)  =  x:y:catpairs xys
 
diff --git a/mk/depend.mk b/mk/depend.mk
--- a/mk/depend.mk
+++ b/mk/depend.mk
@@ -57,10 +57,10 @@
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
   bench/erroneous.hs
-bench/gps2: \
-  bench/gps2.hs \
+bench/gps: \
+  bench/gps.hs \
   mk/toplibs
-bench/gps2.o: \
+bench/gps.o: \
   src/Conjure/Utils.hs \
   src/Conjure/Settings.hs \
   src/Conjure/Red.hs \
@@ -74,11 +74,11 @@
   src/Conjure/Defn.hs \
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
-  bench/gps2.hs
-bench/gps: \
-  bench/gps.hs \
+  bench/gps.hs
+bench/i12: \
+  bench/i12.hs \
   mk/toplibs
-bench/gps.o: \
+bench/i12.o: \
   src/Conjure/Utils.hs \
   src/Conjure/Settings.hs \
   src/Conjure/Red.hs \
@@ -92,11 +92,11 @@
   src/Conjure/Defn.hs \
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
-  bench/gps.hs
-bench/ill-hit: \
-  bench/ill-hit.hs \
+  bench/i12.hs
+bench/i30: \
+  bench/i30.hs \
   mk/toplibs
-bench/ill-hit.o: \
+bench/i30.o: \
   src/Conjure/Utils.hs \
   src/Conjure/Settings.hs \
   src/Conjure/Red.hs \
@@ -110,11 +110,11 @@
   src/Conjure/Defn.hs \
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
-  bench/ill-hit.hs
-bench/longshot: \
-  bench/longshot.hs \
+  bench/i30.hs
+bench/ill-hit: \
+  bench/ill-hit.hs \
   mk/toplibs
-bench/longshot.o: \
+bench/ill-hit.o: \
   src/Conjure/Utils.hs \
   src/Conjure/Settings.hs \
   src/Conjure/Red.hs \
@@ -128,11 +128,11 @@
   src/Conjure/Defn.hs \
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
-  bench/longshot.hs
-bench/lowtests: \
-  bench/lowtests.hs \
+  bench/ill-hit.hs
+bench/longshot: \
+  bench/longshot.hs \
   mk/toplibs
-bench/lowtests.o: \
+bench/longshot.o: \
   src/Conjure/Utils.hs \
   src/Conjure/Settings.hs \
   src/Conjure/Red.hs \
@@ -146,11 +146,11 @@
   src/Conjure/Defn.hs \
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
-  bench/lowtests.hs
-bench/p12: \
-  bench/p12.hs \
+  bench/longshot.hs
+bench/lowtests: \
+  bench/lowtests.hs \
   mk/toplibs
-bench/p12.o: \
+bench/lowtests.o: \
   src/Conjure/Utils.hs \
   src/Conjure/Settings.hs \
   src/Conjure/Red.hs \
@@ -164,11 +164,11 @@
   src/Conjure/Defn.hs \
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
-  bench/p12.hs
-bench/p30: \
-  bench/p30.hs \
+  bench/lowtests.hs
+bench/psb2: \
+  bench/psb2.hs \
   mk/toplibs
-bench/p30.o: \
+bench/psb2.o: \
   src/Conjure/Utils.hs \
   src/Conjure/Settings.hs \
   src/Conjure/Red.hs \
@@ -182,7 +182,7 @@
   src/Conjure/Defn.hs \
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
-  bench/p30.hs
+  bench/psb2.hs
 bench/redundants: \
   bench/redundants.hs \
   mk/toplibs
@@ -399,6 +399,24 @@
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
   eg/colin/ListFuns.hs
+eg/conditionals: \
+  eg/conditionals.hs \
+  mk/toplibs
+eg/conditionals.o: \
+  src/Conjure/Utils.hs \
+  src/Conjure/Settings.hs \
+  src/Conjure/Red.hs \
+  src/Conjure/Reason.hs \
+  src/Conjure.hs \
+  src/Conjure/Ingredient.hs \
+  src/Conjure/Expr.hs \
+  src/Conjure/Engine.hs \
+  src/Conjure/Defn/Test.hs \
+  src/Conjure/Defn/Redundancy.hs \
+  src/Conjure/Defn.hs \
+  src/Conjure/Conjurable.hs \
+  src/Conjure/Conjurable/Derive.hs \
+  eg/conditionals.hs
 eg/count: \
   eg/count.hs \
   mk/toplibs
@@ -417,6 +435,24 @@
   src/Conjure/Conjurable.hs \
   src/Conjure/Conjurable/Derive.hs \
   eg/count.hs
+eg/digits: \
+  eg/digits.hs \
+  mk/toplibs
+eg/digits.o: \
+  src/Conjure/Utils.hs \
+  src/Conjure/Settings.hs \
+  src/Conjure/Red.hs \
+  src/Conjure/Reason.hs \
+  src/Conjure.hs \
+  src/Conjure/Ingredient.hs \
+  src/Conjure/Expr.hs \
+  src/Conjure/Engine.hs \
+  src/Conjure/Defn/Test.hs \
+  src/Conjure/Defn/Redundancy.hs \
+  src/Conjure/Defn.hs \
+  src/Conjure/Conjurable.hs \
+  src/Conjure/Conjurable/Derive.hs \
+  eg/digits.hs
 eg/dupos: \
   eg/dupos.hs \
   mk/toplibs
diff --git a/src/Conjure.hs b/src/Conjure.hs
--- a/src/Conjure.hs
+++ b/src/Conjure.hs
@@ -19,8 +19,8 @@
 --
 -- > ingredients :: [Ingredient]
 -- > ingredients =
--- >   [ unfun (0::Int)
--- >   , unfun (1::Int)
+-- >   [ con (0::Int)
+-- >   , con (1::Int)
 -- >   , fun "+" ((+) :: Int -> Int -> Int)
 -- >   , fun "*" ((*) :: Int -> Int -> Int)
 -- >   , fun "-" ((-) :: Int -> Int -> Int)
@@ -62,9 +62,9 @@
 -- > take' 3 [x,y]  =  [x,y]
 --
 -- > > conjure "take" (take' :: Int -> [A] -> [A])
--- > >   [ unfun (0 :: Int)
--- > >   , unfun (1 :: Int)
--- > >   , unfun ([] :: [A])
+-- > >   [ con (0 :: Int)
+-- > >   , con (1 :: Int)
+-- > >   , con ([] :: [A])
 -- > >   , fun ":" ((:) :: A -> [A] -> [A])
 -- > >   , fun "-" ((-) :: Int -> Int -> Int)
 -- > >   ]
@@ -96,7 +96,7 @@
     conjure
   , Ingredient
   , fun
-  , unfun
+  , con
   , guard
   , iif
   , ordcase
@@ -155,7 +155,7 @@
   , dontRewrite
   , dontRequireDescent
   , omitAssortedPruning
-  , omitEarlyTests
+  , maxEarlyTests
   , dontCopyBindings
   , nonAtomicNumbers
   , uniqueCandidates
@@ -164,7 +164,7 @@
   , Prim
   , pr
   , prim
-  , con
+  , unfun
   )
 where
 
diff --git a/src/Conjure/Conjurable.hs b/src/Conjure/Conjurable.hs
--- a/src/Conjure/Conjurable.hs
+++ b/src/Conjure/Conjurable.hs
@@ -122,9 +122,16 @@
 --
 -- (cf. 'reifyTiers', 'reifyEquality', 'conjureType')
 class (Typeable a, Name a) => Conjurable a where
+  -- | Returns a list of holes matching arguments of the given function.
   conjureArgumentHoles :: a -> [Expr]
   conjureArgumentHoles _  =  []
 
+  -- | Returns a hole with the same type as the given functions final result.
+  conjureResultHole :: a -> Expr
+  conjureResultHole x  =  value "_" (err `asTypeOf` x)
+    where
+    err  =  error "conjureResultHole: placeholder for recursive call?"
+
   -- | Returns 'Just' the '==' function encoded as an 'Expr' when available
   --   or 'Nothing' otherwise.
   --
@@ -610,6 +617,7 @@
 
 instance (Conjurable a, Conjurable b) => Conjurable (a -> b) where
   conjureArgumentHoles f  =  hole (argTy f) : conjureArgumentHoles (f undefined)
+  conjureResultHole f  =  conjureResultHole (f undefined)
   conjureSubTypes f  =  conjureType (argTy f) . conjureType (resTy f)
   conjureIf f  =  conjureIf (f undefined)
   conjureArgumentCases f  =  conjureCases (argTy f) : conjureArgumentCases (f undefined)
diff --git a/src/Conjure/Defn.hs b/src/Conjure/Defn.hs
--- a/src/Conjure/Defn.hs
+++ b/src/Conjure/Defn.hs
@@ -74,17 +74,15 @@
   where
   show1 (lhs,rhs)  =
     case rhs of
-    (Value "|" _ :$ c :$ t :$ e) -> showExpr lhs
-                         ++ "\n  | " ++ showExpr c ++ "  =  " ++ showExpr t
-                         ++ "\n  | otherwise  =  " ++ showExpr e
-    (Value "if" _ :$ c :$ t :$ e) -> lhseqs ++ "if " ++ showExpr c
-                          ++ "\n" ++ spaces ++ "then " ++ showExpr t
-                          ++ "\n" ++ spaces ++ "else " ++ showExpr e
-    (Value "case" _ :$ ep :$ ex :$ ey)
+    Value "|" _ :$ _ :$ _ :$ _ -> showExpr lhs ++ showCases rhs
+    Value "if" _ :$ c :$ t :$ e -> lhseqs ++ "if " ++ showExpr c
+                        ++ "\n" ++ spaces ++ "then " ++ showExpr t
+                        ++ "\n" ++ spaces ++ "else " ++ showExpr e
+    Value "case" _ :$ ep :$ ex :$ ey
       | typ ep == boolTy -> lhseqs ++ "case " ++ showExpr ep ++ " of"
                  ++ "\n" ++ spaces ++ "False -> " ++ showExpr ex
                  ++ "\n" ++ spaces ++ "True  -> " ++ showExpr ey
-    (Value "case" _ :$ eo :$ ex :$ ey :$ ez)
+    Value "case" _ :$ eo :$ ex :$ ey :$ ez
       | typ eo == orderingTy -> lhseqs ++ "case " ++ showExpr eo ++ " of"
                      ++ "\n" ++ spaces ++ "LT -> " ++ showExpr ex
                      ++ "\n" ++ spaces ++ "EQ -> " ++ showExpr ey
@@ -93,6 +91,11 @@
     where
     lhseqs  =  showExpr lhs ++ "  =  "
     spaces  =  map (const ' ') lhseqs
+  showCases (Value "|" _ :$ c :$ e :$ etc)  =
+    "\n  | " ++ showExpr c ++ "  =  " ++ showExpr e ++ showCases etc
+  showCases e  =
+    "\n  | otherwise  =  " ++ showExpr e
+
 
 -- | Pretty-prints a 'Defn' to the screen.
 --
diff --git a/src/Conjure/Defn/Redundancy.hs b/src/Conjure/Defn/Redundancy.hs
--- a/src/Conjure/Defn/Redundancy.hs
+++ b/src/Conjure/Defn/Redundancy.hs
@@ -145,11 +145,21 @@
 -- are at the root: we have a redundant function.
 -- (Modulo error functions, which are undesired anyway.)
 --
+-- Here is an example:
+--
 -- > xs ? []  =  []
 -- > xs ? (x:ys)  =  xs ? ys
 --
 -- Above it does not really pays off to follow the recursive calls,
 -- at the end we always reach an empty list.
+--
+-- Here is a more complex example:
+--
+-- > [] ? xs  =  []
+-- > (x:xs) ? []  =  []
+-- > (x:xs) ? (y:ys)  =  xs ? ys
+--
+-- We are bound to reach [] when following the recursion.
 isRedundantByRootRecursions :: Defn -> Bool
 isRedundantByRootRecursions d  =  case partition isGround $ map snd d of
   ([b], rs@(_:_))  ->  all isHole rs
diff --git a/src/Conjure/Engine.hs b/src/Conjure/Engine.hs
--- a/src/Conjure/Engine.hs
+++ b/src/Conjure/Engine.hs
@@ -47,7 +47,7 @@
   , dontRewrite
   , dontRequireDescent
   , omitAssortedPruning
-  , omitEarlyTests
+  , maxEarlyTests
   , dontCopyBindings
   , nonAtomicNumbers
   , uniqueCandidates
@@ -71,7 +71,7 @@
 
 import Test.LeanCheck
 import Test.LeanCheck.Tiers
-import Test.LeanCheck.Error (errorToFalse)
+import Test.LeanCheck.Error (errorToFalse, errorToLeft)
 
 import Conjure.Expr
 import Conjure.Conjurable
@@ -101,8 +101,8 @@
 -- >
 -- > ingredients :: [Ingredient]
 -- > ingredients  =
--- >   [ unfun (0::Int)
--- >   , unfun (1::Int)
+-- >   [ con (0::Int)
+-- >   , con (1::Int)
 -- >   , fun "+" ((+) :: Int -> Int -> Int)
 -- >   , fun "*" ((*) :: Int -> Int -> Int)
 -- >   , fun "-" ((-) :: Int -> Int -> Int)
@@ -121,7 +121,7 @@
 -- > factorial 0  =  1
 -- > factorial x  =  x * factorial (x - 1)
 --
--- The ingredients list is defined with 'unfun' and 'fun'.
+-- The ingredients list is defined with 'con' and 'fun'.
 conjure :: Conjurable f => String -> f -> [Ingredient] -> IO ()
 conjure nm f  =  conjure0 nm f (const [])
 
@@ -385,7 +385,8 @@
 --   using pattern matching.
 candidateDefnsC :: Conjurable f => String -> f -> [Ingredient] -> ([[Defn]], Thy, [[Defn]], [Expr])
 candidateDefnsC nm f is =
-  ( discardT hasRedundant $ concatMapT fillingsFor fss
+  ( discardT hasRedundant $ catconMapT fillingsFor partialDefns
+  -- above we catconMapT to prefer smaller recursive calls
   , thy
   , mapT (map (,eh)) pats
   , deconstructions
@@ -393,12 +394,12 @@
   where
   pats | maxPatternSize > 0  =  take maxPatternSize $ conjurePats maxPatternDepth es nm f
        | otherwise           =                        conjurePats maxPatternDepth es nm f
-  fss  =  concatMapT ps2fss pats
+  partialDefns  =  concatMapT partialDefnsFromPats pats
   -- replaces the any guard symbol with a guard of the correct type
   ps  =  actual is  -- extract actual ingredients/primitives from the list
   es  =  [if isGuardSymbol e then conjureGuard f else e | (e,_) <- ps]
 
-  eh  =  holeAsTypeOf efxs
+  eh  =  conjureResultHole f
   efxs  =  conjureVarApplication nm f
   (ef:_)  =  unfoldApp efxs
 
@@ -431,43 +432,57 @@
   isNumeric  =  conjureIsNumeric f
 
   (-==-)  =  conjureMkEquation f
+  etests  =  map (first (mappArgs exprExpr)) tests
   tests  =  conjureTestDefn maxTests maxSearchTests nm f
   exprExpr  =  conjureExpress f
 
-  ps2fss :: [Expr] -> [[Defn]]
-  ps2fss pats  =  discardT isRedundant
-               .  products  -- alt: use delayedProducts
-               $  map p2eess pats
+  distritests :: [(Expr,Expr)] -> [Expr] -> [([(Expr,Expr)],Expr)]
+  distritests _ []  =  []
+  distritests ts (pat:pats)  =  (ys, pat) : distritests ns pats
+    where
+    (ys, ns)  =  partition (\(lhs,_) -> lhs `isInstanceOf` pat) ts
+
+  partialDefnsFromPats :: [Expr] -> [[Defn]]
+  partialDefnsFromPats pats  =  discardT isRedundant
+                             .  products  -- alt: use delayedProducts
+                             .  map (uncurry bindingsForPattern)
+                             .  distritests etests
+                             $  pats
     -- delayedProducts makes the number of patterns counts as the size+1.
     where
-    p2eess :: Expr -> [[Bndn]]
+    bindingsForPattern :: [(Expr,Expr)] -> Expr -> [[Bndn]]
     -- the following guarded line is an optional optimization
     -- if the function is defined for the given pattern,
     -- simply use its return value as the only possible result
-    p2eess pat | copyBindings && isGroundPat f pat  =  [[(pat, toValPat f pat)]]
-    p2eess pat  =  mapT (pat,)
-                .  filterT keepBase
-                .  appsWith pat
-                .  drop 1 -- this excludes the function name itself
-                $  vars pat ++ [eh | any (uncurry should) (zip aess aes)]
+    bindingsForPattern ts pat
+      | copyBindings && isGroundPat f pat  =  [[(pat, toValPat f pat)]]
+      | otherwise  =  mapT (pat,)
+                   .  filterT keepB
+                   .  appsWith pat
+                   .  drop 1 -- this excludes the function name itself
+                   $  vars pat ++ [eh | any (uncurry should) (zip aess aes)]
       where
-      keepBase
-        | not earlyTests  =  const True
-        | all isVar (unfoldApp pat)  =  const True
-        | otherwise  =  \e -> hasHole e || reallyKeepBase e
-      reallyKeepBase e  =  and
-        [ errorToFalse $ eval False $ (e //- bs) -==- rhs
-        | (lhs,rhs) <- tests
-        -- filter test bindings that match the current pattern:
-        , Just bs <- [lhs `matchArgs` pat]
+      keepB
+        | maxEarlyTests <= 0  =  const True
+        | length pats < 2  =  const True  -- just one pat, test later
+        | otherwise  =  \e -> isNumeric eh && hasHole e || reallyKeepB e
+      reallyKeepB e  =  and
+        [ errholeToTrue $ eval False $ (e //- bs) -==- rhs
+        | (lhs,rhs) <- take maxEarlyTests ts
+        , Just bs <- [lhs `match` pat]  -- always should match
         ]
-      matchArgs efxs efys  =  fold (map exprExpr (drop 1 (unfoldApp efxs)))
-                      `match` fold               (drop 1 (unfoldApp efys))
 
-      -- computes whether we should include a recurse for this given argument
-      -- numeric arguments additionally require 0 to be present as a case
-      -- for recursion
-      should aes ae  =  length (nub aes) > 1 && hasVar ae && (isApp ae || isUnbreakable ae)
+      -- computes whether we should include a recurse for this given argument:
+      -- 1. more than one LHS pattern overall
+      -- 2. there should be at least a variable
+      -- 3. it should either:
+      --    * we do not require descent
+      --    * be a breakdown such as _:_ or Tree _ _ _
+      --    * or be of an unbreakable/atomic type such as (_ :: Int)
+      --      in the presence of deconstructions
+      should aes ae  =  length (nub aes) > 1
+                     && hasVar ae
+                     && (not requireDescent || isApp ae || isUnbreakable ae && notNull deconstructions)
       aes   =                  (tail . unfoldApp . rehole) pat
       aess  =  transpose $ map (tail . unfoldApp . rehole) pats
 
@@ -546,7 +561,7 @@
   maxPatternDepth        =  maxPatternDepthI is
   maxPatternSize         =  maxPatternSizeI is
   requireDescent         =  requireDescentI is
-  earlyTests             =  earlyTestsI is
+  maxEarlyTests          =  maxEarlyTestsI is
   copyBindings           =  copyBindingsI is
   adHocRedundancy        =  assortedPruningI is -- TODO: rename
   atomicNumbers          =  atomicNumbersI is
@@ -692,3 +707,16 @@
 
 testSpec :: Int -> [Property] -> Bool
 testSpec maxTests  =  and . map (and . take maxTests)
+
+-- like errorToFalse, but returns True upon finding a placeholder hole
+errholeToTrue :: Bool -> Bool
+errholeToTrue p  =  case errorToLeft p of
+                    Right q -> q
+                    Left "conjureResultHole: placeholder for recursive call?" -> True
+                    Left _ -> False
+
+
+catconMapT :: (a -> [[b]]) -> [[a]] -> [[b]]
+catconMapT f  =  foldr (\+:/) [] . map (foldr (\/) []) . mapT f
+  where
+  xss \+:/ yss  =  ([]:yss) \/ xss
diff --git a/src/Conjure/Expr.hs b/src/Conjure/Expr.hs
--- a/src/Conjure/Expr.hs
+++ b/src/Conjure/Expr.hs
@@ -40,6 +40,8 @@
   , isGuard
   , hasGuard
   , mapInnerFirstOuterLast
+  , mappArgs
+  , mappFun
 
   , enumerateAppsFor
   , enumerateFillings
@@ -70,7 +72,7 @@
 import Data.Dynamic
 -- import Control.Applicative ((<$>)) -- for GHC <= 7.8
 
-import Test.LeanCheck (mapT, filterT, (\/), delay, productWith)
+import Test.LeanCheck (mapT, filterT, (\/), delay, productWith, concatMapT)
 import Test.LeanCheck.Tiers (products)
 import Test.LeanCheck.Utils.Types (A, B, C, D, E, F)
 
@@ -375,11 +377,15 @@
   for h  =  filter (\e -> typ h == typ e) es : apps
     where
     apps  =  foldr (\/) []
-          [  filterT keep $ fliproductWith (:$) (ufor hf) (ufor hx)
+          [  filterT keep $ concatMapT afor (ufor hf)
           |  hf <- hs
           ,  hx <- hs
           ,  Just hfx <- [hf $$ hx]
           ,  typ h == typ hfx
+          -- the following allows chains of guards:
+          , let afor ef  =  mapT (ef :$) $ if isGuard (ef :$ hx)
+                                           then for hx
+                                           else ufor hx
           ]
   -- unguarded for
   ufor | any isGuardSymbol es  =  filterT (not . isGuard) . for
@@ -640,6 +646,20 @@
   where
   m (ef :$ ex)  =  f (m ef :$ m ex)
   m e  =  f e
+
+-- TODO: move mappArgs to Express?
+mappArgs :: (Expr -> Expr) -> Expr -> Expr
+mappArgs f  =  m
+  where
+  m (ef :$ ex)  =  m ef :$ f ex
+  m e  =  e
+
+-- TODO: move mappFun to Express?
+mappFun :: (Expr -> Expr) -> Expr -> Expr
+mappFun f  =  m
+  where
+  m (ef :$ ex)  =  m ef :$ ex
+  m ef  =  f ef
 
 instance Express A where  expr  =  val
 instance Express B where  expr  =  val
diff --git a/src/Conjure/Ingredient.hs b/src/Conjure/Ingredient.hs
--- a/src/Conjure/Ingredient.hs
+++ b/src/Conjure/Ingredient.hs
@@ -12,7 +12,7 @@
 module Conjure.Ingredient
   ( Ingredient
   , fun
-  , unfun
+  , con
   , iif
   , ordcase
   , guard
@@ -25,7 +25,7 @@
   , prim
   , prif
   , primOrdCaseFor
-  , con
+  , unfun
   )
 where
 
@@ -36,12 +36,12 @@
 
 
 -- | A single functional ingredient in conjuring.
--- Specify conjure ingredients with 'unfun' and 'fun':
+-- Specify conjure ingredients with 'con' and 'fun':
 --
--- > conjure "foo" foo [ unfun False
--- >                   , unfun True
--- >                   , unfun (0 :: Int)
--- >                   , unfun (1 :: Int)
+-- > conjure "foo" foo [ con False
+-- >                   , con True
+-- >                   , con (0 :: Int)
+-- >                   , con (1 :: Int)
 -- >                   , ...
 -- >                   , fun "&&" (&&)
 -- >                   , fun "||" (||)
@@ -53,9 +53,9 @@
 --
 -- Ingredients may include arbitrary
 -- functional values ('fun')
--- and non-functional values ('unfun').
+-- and non-functional (constant) values ('con').
 -- These may be built-in or user defined.
--- Use 'unfun' on 'Show' instances
+-- Use 'con' on 'Show' instances
 -- and 'fun' otherwise.
 --
 -- This is internally
@@ -65,26 +65,26 @@
 type Ingredient  =  (Expr, Reification)
 
 
--- | Provided a 'Show'-able non-functional value to Conjure.
+-- | Provides a 'Show'-able non-functional constant value to Conjure.
 --   (cf. 'fun')
 --
--- > conjure "foo" foo [ unfun False
--- >                   , unfun True
--- >                   , unfun (0 :: Int)
--- >                   , unfun (1 :: Int)
+-- > conjure "foo" foo [ con False
+-- >                   , con True
+-- >                   , con (0 :: Int)
+-- >                   , con (1 :: Int)
 -- >                   , ...
 -- >                   ]
 --
 -- Argument types have to be monomorphized,
 -- so use type bindings when applicable.
-unfun :: (Conjurable a, Show a) => a -> Ingredient
-unfun x  =  (val x, conjureType x)
+con :: (Conjurable a, Show a) => a -> Ingredient
+con x  =  (val x, conjureType x)
 
 
 -- | Provides a functional value as an ingredient to Conjure.
 --   To be used on values that are not 'Show' instances
 --   such as functions.
---   (cf. 'unfun')
+--   (cf. 'con')
 --
 -- > conjure "foo" foo [ ...
 -- >                   , fun "&&" (&&)
@@ -112,7 +112,7 @@
 -- > last' [x,y]  =  y
 -- > last' [x,y,z]  =  z
 --
--- > > conjure "last" last' [ unfun ([] :: [Int])
+-- > > conjure "last" last' [ con ([] :: [Int])
 -- > >                      , fun ":" ((:) :: Int -> [Int] -> [Int])
 -- > >                      , fun "null" (null :: [Int] -> Bool)
 -- > >                      , iif (undefined :: Int)
@@ -142,7 +142,7 @@
 -- > last' [x,y,z]  =  z
 --
 -- > > conjure "last" last'
--- > >   [ unfun ([] :: [Int])
+-- > >   [ con ([] :: [Int])
 -- > >   , fun ":" ((:) :: Int -> [Int] -> [Int])
 -- > >   , fun "null" (null :: [Int] -> Bool)
 -- > >   , guard
@@ -174,8 +174,8 @@
 -- This should be used when one wants Conjure to consider ord-case expressions:
 --
 -- > > conjure "mem" mem
--- > >   [ unfun False
--- > >   , unfun True
+-- > >   [ con False
+-- > >   , con True
 -- > >   , fun "`compare`" (compare :: Int -> Int -> Ordering)
 -- > >   , ordcase (undefined :: Bool)
 -- > >   ]
@@ -273,7 +273,7 @@
 primOrdCaseFor  =  ordcase
 {-# DEPRECATED primOrdCaseFor "'primOrdCaseFor' is deprecated, please use 'ordcase' instead" #-}
 
--- | __DEPRECATED__. Please use 'unfun' instead.
-con :: (Conjurable a, Show a) => a -> Ingredient
-con  =  unfun
-{-# DEPRECATED con "'con' is deprecated, please use 'unfun' instead" #-}
+-- | __DEPRECATED__. Please use 'con' instead.
+unfun :: (Conjurable a, Show a) => a -> Ingredient
+unfun  =  con
+{-# DEPRECATED unfun "'unfun' is deprecated, please use 'con' instead" #-}
diff --git a/src/Conjure/Settings.hs b/src/Conjure/Settings.hs
--- a/src/Conjure/Settings.hs
+++ b/src/Conjure/Settings.hs
@@ -40,7 +40,7 @@
   , dontRewrite
   , dontRequireDescent
   , omitAssortedPruning
-  , omitEarlyTests
+  , maxEarlyTests
   , dontCopyBindings
   , nonAtomicNumbers
   , uniqueCandidates
@@ -74,7 +74,7 @@
   , rewriteI
   , requireDescentI
   , assortedPruningI
-  , earlyTestsI
+  , maxEarlyTestsI
   , copyBindingsI
   , atomicNumbersI
   , uniqueCandidatesI
@@ -117,7 +117,7 @@
   | DontRewrite          -- ^ turns off unique-modulo-rewriting candidates
   | DontRequireDescent   -- ^ require recursive calls to deconstruct arguments
   | OmitAssortedPruning  -- ^ omit other assorted pruning rules
-  | OmitEarlyTests       -- ^ don't perform tests early-and-independently on each binding
+  | MaxEarlyTests Int    -- ^ don't perform tests early-and-independently on each binding
   | DontCopyBindings     -- ^ don't copy partial definition bindings in candidates
   | AtomicNumbers        -- ^ restrict constant/ground numeric expressions to atoms
   | NonAtomicNumbers     -- ^ lift constant/ground numetic expression restrictions
@@ -379,14 +379,17 @@
 assortedPruningI :: [Ingredient] -> Bool
 assortedPruningI is  =  null [False | OmitAssortedPruning <- map extract is]
 
--- | Omits early tests
+-- | Sets the maximum number of early tests
+--   performed independently bindings/equations
 --   when provided in the ingredient list
 --   of 'Conjure.conjure' or 'Conjure.conjureFromSpec'.
-omitEarlyTests :: Ingredient
-omitEarlyTests  =  setting OmitEarlyTests
+--
+--   When not set, this defaults to a modest 12.
+maxEarlyTests :: Int -> Ingredient
+maxEarlyTests  =  setting . MaxEarlyTests
 
-earlyTestsI :: [Ingredient] -> Bool
-earlyTestsI is  =  null [False | OmitEarlyTests <- map extract is]
+maxEarlyTestsI :: [Ingredient] -> Int
+maxEarlyTestsI is  =  headOr 12 [m | MaxEarlyTests m <- map extract is]
 
 -- | Disables the copy-bindings rule
 --   when provided in the ingredient list
diff --git a/src/Conjure/Utils.hs b/src/Conjure/Utils.hs
--- a/src/Conjure/Utils.hs
+++ b/src/Conjure/Utils.hs
@@ -26,7 +26,6 @@
 #endif
   , idIO
   , mapHead
-  , sets
   , headOr
   , notNull
   , allEqual
@@ -137,15 +136,6 @@
 mapHead :: (a -> a) -> [a] -> [a]
 mapHead f (x:xs)  =  f x : xs
 mapHead f []  =  error "Conjure.Utils.mapHead: empty list"
-
--- | Return sets of values based on the list.
---
--- The values in the list must me unique.
-sets :: [a] -> [[a]]
-sets []  =  [[]]
-sets (x:xs)  =  map (x:) ss ++ ss
-  where
-  ss  =  sets xs
 
 -- | Like 'head' but allows providing a default value.
 headOr :: a -> [a] -> a
diff --git a/test/factorial.hs b/test/factorial.hs
--- a/test/factorial.hs
+++ b/test/factorial.hs
@@ -13,8 +13,8 @@
 main :: IO ()
 main  =  do
   conjure "factorial n" factorial
-    [ unfun (0::Int)
-    , unfun (1::Int)
+    [ con (0::Int)
+    , con (1::Int)
     , fun "+" ((+) :: Int -> Int -> Int)
     , fun "*" ((*) :: Int -> Int -> Int)
     , fun "-" ((-) :: Int -> Int -> Int)
diff --git a/test/utils.hs b/test/utils.hs
--- a/test/utils.hs
+++ b/test/utils.hs
@@ -16,11 +16,6 @@
   , holds n $ \xs ys -> length xs >= length ys
                     ==> zipWith (<>) xs (ys <> repeat mempty) == mzip xs (ys :: [[Int]])
 
-  , sets []  ==  [[] :: [Int]]
-  , sets [1]  ==  [[1], [] :: [Int]]
-  , sets [1,2]  ==  [[1,2], [1], [2], [] :: [Int]]
-  , sets [1,2,3]  ==  [[1,2,3],[1,2],[1,3],[1],[2,3],[2],[3],[] :: [Int]]
-
   , prods [ [1], [2], [3] ] == [[1,2,3]]
   , prods [ [1,2], [3,4], [5] ] == [[1,3,5],[1,4,5],[2,3,5],[2,4,5]]
   , prods [ [1,2], [3], [4,5] ] == [[1,3,4],[1,3,5],[2,3,4],[2,3,5]]