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:            0.2.8.1
+Version:            0.2.9
 License:            BSD3
 License-File:       COPYRIGHT
 Author:             Martin Erwig <erwig@eecs.oregonstate.edu>, Steve Kollmansberger
@@ -30,7 +30,7 @@
 Source-Repository this
   type:     darcs
   location: http://code.haskell.org/~thielema/probability/
-  tag:      0.2.8.1
+  tag:      0.2.9
 
 
 Flag splitBase
@@ -38,6 +38,7 @@
 
 Library
   Build-Depends:
+    non-empty >=0.3 && <0.4,
     utility-ht >=0.0.12 && <0.1,
     transformers >=0.4 && <0.7
   If flag(splitBase)
@@ -75,6 +76,7 @@
     Numeric.Probability.Example.Kruskal
     Numeric.Probability.Example.MontyHall
     Numeric.Probability.Example.NBoys
+    Numeric.Probability.Example.Histogram
     Numeric.Probability.Example.Predator
     Numeric.Probability.Example.Profession
     Numeric.Probability.Example.Queuing
diff --git a/src/Numeric/Probability/Example/Dice.hs b/src/Numeric/Probability/Example/Dice.hs
--- a/src/Numeric/Probability/Example/Dice.hs
+++ b/src/Numeric/Probability/Example/Dice.hs
@@ -10,7 +10,7 @@
 type Probability = Rational
 type Dist = Dist.T Probability
 
-die :: Dist Die
+die :: Fractional prob => Dist.T prob Die
 die = Dist.uniform [1..6]
 
 -- | product of independent distributions
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
@@ -14,16 +14,13 @@
 import qualified Numeric.Probability.Monad as MonadExt
 import Numeric.Probability.Trace (Trace)
 
-import Numeric.Probability.Example.Dice (Die, )
+import Numeric.Probability.Example.Dice (die)
 
 import Data.Maybe.HT (toMaybe)
 
 
 type Score = Int
 
-
-die :: Fractional prob => Dist.T prob Die
-die = Dist.uniform [1..6]
 
 roll :: Fractional prob => Trans.T prob (Maybe Score)
 roll =
diff --git a/src/Numeric/Probability/Example/Histogram.hs b/src/Numeric/Probability/Example/Histogram.hs
new file mode 100644
--- /dev/null
+++ b/src/Numeric/Probability/Example/Histogram.hs
@@ -0,0 +1,116 @@
+{- |
+We have a set of symbols.
+We draw from this set n times with replacement.
+We then sort the symbols by their drawn frequency.
+What is the expected distribution of the histogram?
+-}
+module Numeric.Probability.Example.Histogram where
+
+import qualified Numeric.Probability.Distribution as Dist
+import Control.Monad (replicateM, guard)
+
+import qualified Data.NonEmpty as NonEmpty
+import qualified Data.IntMap as IntMap
+import qualified Data.Map as Map
+import Data.Foldable (for_)
+import Data.IntMap (IntMap)
+import Data.Map (Map)
+
+import Text.Printf (printf)
+
+{- $setup
+>>> import qualified Combinatorics as Comb
+-}
+
+
+example :: (Ord a) => NonEmpty.T [] a -> Int -> Dist.T Rational (Map Int Int)
+example set n = Dist.norm $ do
+   let x = NonEmpty.head set
+   xs <- replicateM (n-1) $ Dist.uniform $ NonEmpty.flatten set
+   return $ histogram $ Map.elems $ histogram (x:xs)
+
+flattenHistogram :: (Num a) => Map Int a -> [a]
+flattenHistogram histo =
+   Map.elems $ Map.unionWith (+) histo $ Map.fromList $
+   decorate 0 [1 .. fst $ Map.findMax histo]
+
+{- |
+>>> exampleList ('a'!:['b'..'k']) 4
+fromFreqs [([4],720 % 1331),([2,1],540 % 1331),([1,0,1],40 % 1331),([0,2],30 % 1331),([0,0,0,1],1 % 1331)]
+-}
+exampleList :: (Ord a) => NonEmpty.T [] a -> Int -> Dist.T Rational [Int]
+exampleList set n = fmap flattenHistogram $ example set n
+
+histogram :: (Ord a) => [a] -> Map a Int
+histogram = Map.fromListWith (+) . decorate 1
+
+decorate :: b -> [a] -> [(a,b)]
+decorate label = map (flip (,) label)
+
+
+{-
+3: https://oeis.org/A038207
+4: https://oeis.org/A027465
+5: https://oeis.org/A038231
+6: https://oeis.org/A038243
+7: https://oeis.org/A038255
+8: https://oeis.org/A027466
+9: https://oeis.org/A038279
+
+expected $ example [1..k] n
+j -> binomial n j * (k-1)^(n-j)
+
+This also counts the symbols with zero occurrences.
+
+We might prove this using a recurrence.
+-}
+expected :: Dist.T Rational (Map Int Int) -> Map Int Rational
+expected =
+   foldl (Map.unionWith (+)) Map.empty .
+   map (\(x,p) -> fmap ((p*) . fromIntegral) x) .
+   Dist.decons
+
+visualize :: Rational -> Map Int Rational -> IO ()
+visualize scale m =
+   for_ [1 .. fst $ Map.findMax m] $ \n ->
+      let freq = Map.findWithDefault 0 n m in
+      printf "%6.1f %s\n" (fromRational freq :: Double) $
+         replicate (round (scale * freq)) '*'
+
+
+
+{-
+https://oeis.org/A000041
+
+>>> map (\n -> length $ partitions n n) [0..20]
+-}
+partitions :: Int -> Int -> [IntMap Int]
+partitions maxBin =
+   let go total multi =
+         case compare multi 1 of
+            LT -> guard (total == 0) >> [IntMap.empty]
+            EQ -> guard (total <= maxBin) >> [IntMap.singleton multi total]
+            GT ->
+               concat $
+               zipWith
+                  (\j amount ->
+                     map (IntMap.singleton multi j <>) $
+                     go (total-amount) (multi-1))
+                  [0..maxBin]
+                  [0,multi..total]
+   in \total -> go total total
+
+{-
+*Numeric.Probability.Visualize NE GP Comb> GP.plotList [] $ zipWith (*) (map fromInteger $ Comb.binomialSeq 110) (iterate (/27) ((27/28)**110::Double))
+*Numeric.Probability.Visualize NE GP Comb> let xs = zipWith (*) (map fromInteger $ Comb.binomialSeq 110) (iterate (/27) ((27/28)**110::Double))
+*Numeric.Probability.Visualize NE GP Comb> sum xs
+1.0000000000000022
+
+
+let histo n k = map (% k^(n-1)) $ zipWith (*) (Comb.binomialSeq n) (reverse $ take (fromInteger $ n+1) $ iterate (*(k-1)) 1)
+
+>>> sum $ histo 110 28
+28 % 1
+>>> sum $ zipWith (*) [0..] $ histo 110 28
+110 % 1
+-}