diff --git a/probability.cabal b/probability.cabal
--- a/probability.cabal
+++ b/probability.cabal
@@ -1,6 +1,6 @@
 Cabal-Version:      1.24
 Name:               probability
-Version:            0.2.8
+Version:            0.2.8.1
 License:            BSD3
 License-File:       COPYRIGHT
 Author:             Martin Erwig <erwig@eecs.oregonstate.edu>, Steve Kollmansberger
@@ -14,14 +14,15 @@
    The monad is similar to the List monad for non-deterministic computations,
    but extends the List monad by a measure of probability.
    Small interface to R plotting.
-Tested-With:    GHC==7.0.2, GHC==7.2.2, GHC==7.4.2, GHC==7.8.2
-Tested-With:    GHC==8.6.5, GHC==8.8.3
+Tested-With:    GHC==7.*, GHC==8.*, GHC==9.*
 Build-Type:     Simple
 Extra-Source-Files:
-  Changes.md
   README
   ToDo
 
+Extra-Doc-Files:
+  Changes.md
+
 Source-Repository head
   type:     darcs
   location: http://code.haskell.org/~thielema/probability/
@@ -29,7 +30,7 @@
 Source-Repository this
   type:     darcs
   location: http://code.haskell.org/~thielema/probability/
-  tag:      0.2.8
+  tag:      0.2.8.1
 
 
 Flag splitBase
@@ -41,8 +42,8 @@
     transformers >=0.4 && <0.7
   If flag(splitBase)
     Build-Depends:
-      containers >=0.1 && <0.7,
-      random >=1.0 && <1.3,
+      containers >=0.1 && <0.9,
+      random >=1.0 && <1.4,
       base >=2 && <5
   Else
     Build-Depends:
diff --git a/src/Numeric/Probability/Example/Alarm.hs b/src/Numeric/Probability/Example/Alarm.hs
--- a/src/Numeric/Probability/Example/Alarm.hs
+++ b/src/Numeric/Probability/Example/Alarm.hs
@@ -42,20 +42,22 @@
 m a0 = if a0 then flp 0.9 else flp 0.1
 
 -- | calculate the full joint distribution
-data Burglary = B { 	burglary :: Bool,
-			earthquake :: Bool,
-			alarm :: Bool,
-			john :: Bool,
-			mary :: Bool }
-	deriving (Eq, Ord, Show)
+data Burglary =
+   B {
+      burglary :: Bool,
+      earthquake :: Bool,
+      alarm :: Bool,
+      john :: Bool,
+      mary :: Bool
+   } deriving (Eq, Ord, Show)
 
 bJoint :: Dist Burglary
-bJoint = do b' <- b 		-- burglary
-            e' <- e 		-- earthquake
-            a' <- a b' e' 	-- alarm
-	    j' <- j a' 		-- john
-	    m' <- m a' 		-- mary
-	    return (B b' e' a' j' m')
+bJoint = do b' <- b             -- burglary
+            e' <- e             -- earthquake
+            a' <- a b' e'       -- alarm
+            j' <- j a'          -- john
+            m' <- m a'          -- mary
+            return (B b' e' a' j' m')
 
 -- | what is the probability that mary calls given that john calls?
 pmj :: Probability
diff --git a/src/Numeric/Probability/Example/Barber.hs b/src/Numeric/Probability/Example/Barber.hs
--- a/src/Numeric/Probability/Example/Barber.hs
+++ b/src/Numeric/Probability/Example/Barber.hs
@@ -45,7 +45,7 @@
 -- * category
 
 data Category = ThreeOrLess | FourToTen | MoreThanTen
-	deriving (Eq,Ord,Show)
+   deriving (Eq,Ord,Show)
 
 cat :: Time -> Category
 cat n | n <= 3 = ThreeOrLess
diff --git a/src/Numeric/Probability/Example/DiceAccum.hs b/src/Numeric/Probability/Example/DiceAccum.hs
--- a/src/Numeric/Probability/Example/DiceAccum.hs
+++ b/src/Numeric/Probability/Example/DiceAccum.hs
@@ -16,7 +16,9 @@
 
 import Numeric.Probability.Example.Dice (Die, )
 
+import Data.Maybe.HT (toMaybe)
 
+
 type Score = Int
 
 
@@ -26,13 +28,9 @@
 roll :: Fractional prob => Trans.T prob (Maybe Score)
 roll =
    maybe
-     (return Nothing)
-     (\score -> flip fmap die $
-         \spots ->
-            -- where is my beloved 'toMaybe' ?
-            if spots == 3
-              then Nothing
-              else Just (score + spots))
+      (return Nothing)
+      (\score -> flip fmap die $
+         \spots -> toMaybe (spots /= 3) (score + spots))
 
 continue :: Score -> Bool
 continue scoreInt =
diff --git a/src/Numeric/Probability/Example/Queuing.hs b/src/Numeric/Probability/Example/Queuing.hs
--- a/src/Numeric/Probability/Example/Queuing.hs
+++ b/src/Numeric/Probability/Example/Queuing.hs
@@ -62,15 +62,15 @@
 
 mEvent :: Int -> Time -> Events a -> Queue a -> [State a]
 mEvent _ _ [] []             =        []
-mEvent n 0 ((c,(s,a)):es) q  = 	      mEvent n a     es (q++[(c,s)])
+mEvent n 0 ((c,(s,a)):es) q  =        mEvent n a     es (q++[(c,s)])
 mEvent n a es []             = ([],a):mEvent n 0     es []
-mEvent n _ [] q		     =  (q,s):mEvent n 0     [] (mServe n s q)
-	where s = mTimeStep n q
+mEvent n _ [] q              =  (q,s):mEvent n 0     [] (mServe n s q)
+        where s = mTimeStep n q
 mEvent n a es q =
    if a < s
      then (q,a) : mEvent n 0     es (mServe n a q)
      else (q,s) : mEvent n (a-s) es (mServe n s q)
-	where s = mTimeStep n q
+        where s = mTimeStep n q
 
 
 -- | decrease served customers remaining time by specified amount
@@ -103,15 +103,15 @@
 
 rSystem :: Int -> REvents a -> Rnd.T (System a)
 rSystem n re = do
-		e <- rBuildEvents re
-		return (mSystem n e)
+   e <- rBuildEvents re
+   return (mSystem n e)
 
 rBuildEvents :: REvents a -> Rnd.T (Events a)
 rBuildEvents ((a,(dt,tt)):ex) = do
-			rest <- rBuildEvents ex
-			t <- Rnd.pick dt
-			nt <- Rnd.pick $ tt t
-			return ((a,(t,nt)):rest)
+   rest <- rBuildEvents ex
+   t <- Rnd.pick dt
+   nt <- Rnd.pick $ tt t
+   return ((a,(t,nt)):rest)
 rBuildEvents [] = return []
 
 rmSystem :: Ord a => Int -> Int -> REvents a -> RDist (System a)
diff --git a/src/Numeric/Probability/Example/TreeGrowth.hs b/src/Numeric/Probability/Example/TreeGrowth.hs
--- a/src/Numeric/Probability/Example/TreeGrowth.hs
+++ b/src/Numeric/Probability/Example/TreeGrowth.hs
@@ -20,7 +20,7 @@
 type Height = Int
 
 data Tree = Alive Height | Hit Height | Fallen
-	    deriving (Ord,Eq,Show)
+   deriving (Ord,Eq,Show)
 
 grow :: Trans Tree
 grow (Alive h) = Dist.normal (map Alive [h+1..h+5])
@@ -103,9 +103,8 @@
 myPlot2 = figP figure{title="Tree Growth",xLabel="Height (m)",
                 yLabel="Probability"}
                 (autoColor [
-		plotD ((5 *. evolve) (Alive 0) >>= height)
-		])
-
+                  plotD ((5 *. evolve) (Alive 0) >>= height)
+                ])
 --}
 
 p1, p2, p3, p4, p5, p6 :: Vis
@@ -117,7 +116,7 @@
 p3 = figP figure{title="Tree Growth",
             xLabel="Height (ft)",
             yLabel="Probability"}
-	    [plotD $ Dist.map height (tree 5 seed)]
+            [plotD $ Dist.map height (tree 5 seed)]
 
 
 p4 = figP figure{title="Tree Growth",
@@ -140,7 +139,7 @@
             xLabel="Height (ft)",
             yLabel="Probability"}
             (map heightCurve
-	    [(3,Blue),(5,Green),(7,Red)])
+            [(3,Blue),(5,Green),(7,Red)])
 
 
 done :: Tree -> Bool
diff --git a/src/Numeric/Probability/Visualize.hs b/src/Numeric/Probability/Visualize.hs
--- a/src/Numeric/Probability/Visualize.hs
+++ b/src/Numeric/Probability/Visualize.hs
@@ -1,5 +1,6 @@
 module Numeric.Probability.Visualize where
 
+import qualified Numeric.Probability.Distribution as Dist
 import qualified Numeric.Probability.Random as Rnd
 import Numeric.Probability.Expectation
     (ToFloat, FromFloat, toFloat, fromFloat, )
@@ -7,10 +8,9 @@
     (Dist, RDist, )
 import Numeric.Probability.PrintList (asTuple, )
 
-import qualified Numeric.Probability.Distribution as Dist
+import qualified Data.Set as Set
 
 import Control.Monad (when, )
-import Data.List (nub, sort, )
 
 
 {- TO DO:
@@ -122,7 +122,7 @@
 --
 plotD :: ToFloat a => Dist a -> Plot
 --plotD d = plot{ys = map (\x->(dp $ prob' x d')) (extract d'),
---		xs = extract d'}
+--               xs = extract d'}
 plotD d =
    let (tfl, pdl) =
           unzip $ Dist.sortElem $
@@ -156,9 +156,9 @@
 
 yls :: [Float] -> Plot -> Plot
 yls xl p = p{xs=x', ys=y'}
-	where 	t = zip (xs p) (ys p)
-		t' = metaTuple xl t
-		(x', y') = unzip t'
+   where t = zip (xs p) (ys p)
+         t' = metaTuple xl t
+         (x', y') = unzip t'
 
 metaTuple :: [Float] -> [(Float,Float)] -> [(Float,Float)]
 metaTuple (x:xl) ((p,v):px) | p == x = (p,v):(metaTuple xl px)
@@ -189,11 +189,18 @@
 fig :: [Plot] -> Vis
 fig = figP figure
 
+
+{- |
+Example session:
+
+> *Numeric.Probability.Visualize> figP figure [plotL [3,1,4,1,5,9::Float]]
+> *Numeric.Probability.Visualize> :! Rscript FuSE.R
+-}
 figP :: FigureEnv -> [Plot] -> Vis
-figP fe ps = do let xl = sort $ nub $ concatMap xs ps
-                let minx = minimum xl
---                let maxx = maximum xl
-                let n = length xl
+figP fe ps = do let xset = Set.fromList $ concatMap xs ps
+                let minx = Set.findMin xset
+                let n = Set.size xset
+                let xl = Set.toList xset
                 let ys' = map ys (map (yls xl) ps) -- yls xl ps
                 let miny = minimum (map minimum ys')
                 let maxy = maximum (map maximum ys')