diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright Tony Day (c) 2017
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Tony Day nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/numhask-histogram.cabal b/numhask-histogram.cabal
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--- /dev/null
+++ b/numhask-histogram.cabal
@@ -0,0 +1,60 @@
+-- This file has been generated from package.yaml by hpack version 0.18.1.
+--
+-- see: https://github.com/sol/hpack
+
+name:           numhask-histogram
+version:        0.0.0.1
+synopsis:       See readme.md
+description:    See readme.md for description.
+category:       project
+homepage:       https://github.com/tonyday567/numhask-histogram#readme
+bug-reports:    https://github.com/tonyday567/numhask-histogram/issues
+author:         Tony Day
+maintainer:     tonyday567@gmail.com
+copyright:      Tony Day (c) 2017
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+cabal-version:  >= 1.10
+
+extra-source-files:
+    stack.yaml
+
+source-repository head
+  type: git
+  location: https://github.com/tonyday567/numhask-histogram
+
+library
+  hs-source-dirs:
+      src
+  ghc-options: -Wall
+  build-depends:
+      base >=4.7 && <5
+    , protolude
+    , containers
+    , foldl
+    , numhask
+    , numhask-range
+    , tdigest
+  exposed-modules:
+      NumHask.Histogram
+  other-modules:
+      Paths_numhask_histogram
+  default-language: Haskell2010
+
+test-suite test
+  type: exitcode-stdio-1.0
+  main-is: test.hs
+  hs-source-dirs:
+      test
+  build-depends:
+      base >=4.7 && <5
+    , protolude
+    , HUnit
+    , QuickCheck
+    , doctest
+    , protolude
+    , tasty
+    , tasty-hunit
+    , tasty-quickcheck
+  default-language: Haskell2010
diff --git a/src/NumHask/Histogram.hs b/src/NumHask/Histogram.hs
new file mode 100644
--- /dev/null
+++ b/src/NumHask/Histogram.hs
@@ -0,0 +1,118 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# OPTIONS_GHC -Wall #-}
+
+module NumHask.Histogram
+  ( Histogram(..)
+  , DealOvers(..)
+  , fill
+  , regular
+  , makeRects
+  , regularQuantiles
+  , quantileFold
+  , fromQuantiles
+  , freq
+  ) where
+
+import Data.TDigest
+import NumHask.Prelude
+import NumHask.Range
+import NumHask.Rect
+import NumHask.Space
+import qualified Data.Map as Map
+import qualified Control.Foldl as L
+import qualified Data.List
+
+-- | a Histogram is a list of contiguous boundaries (a boundary being the lower edge of one bucket and the upper edge of another), and a count for each bucket
+-- Overs and Unders are counted in key=0 and key=length cut
+data Histogram = Histogram
+   { cuts   :: [Double] -- bucket boundaries
+   , values :: Map.Map Int Double -- bucket counts
+   } deriving (Show, Eq)
+
+-- | whether or not to ignore unders and overs
+data DealOvers = IgnoreOvers | IncludeOvers Double
+
+-- | fill a Histogram using pre-specified cuts
+-- >>> fill [0,50,100] [1..100]
+-- Histogram {cuts = [0.0,50.0,100.0], values = fromList [(1,50.0),(2,50.0)]}
+fill :: (Functor f, Foldable f) => [Double] -> f Double -> Histogram
+fill cs xs = Histogram cs (histMap cs xs)
+  where
+    histMap cs' xs' = L.fold count $
+        (\x -> L.fold countBool (fmap (x >) cs')) <$> xs'
+    count = L.premap (\x -> (x,1.0)) countW
+    countBool = L.Fold (\x a -> x + if a then 1 else 0) 0 identity
+    countW = L.Fold (\x (a,w) -> Map.insertWith (+) a w x) Map.empty identity
+
+-- | make a histogram using n equally spaced cuts over the entire range of the data
+-- >>> regular 4 [0..100]
+-- Histogram {cuts = [0.0,25.0,50.0,75.0,100.0], values = fromList [(0,1.0),(1,25.0),(2,25.0),(3,25.0),(4,25.0)]}
+--
+regular :: Int -> [Double] -> Histogram
+regular n xs = fill cs xs
+  where
+    cs = grid OuterPos (space xs :: Range Double) n
+
+-- | transform a Histogram to Rects
+-- >>> makeRects IgnoreOvers (regular 4 [0..100])
+-- [Rect 0.0 25.0 0.0 0.25,Rect 25.0 50.0 0.0 0.25,Rect 50.0 75.0 0.0 0.25,Rect 75.0 100.0 0.0 0.25]
+--
+makeRects :: DealOvers -> Histogram -> [Rect Double]
+makeRects o (Histogram cs counts) = Data.List.zipWith4 Rect x z y w'
+  where
+    y = repeat 0
+    w = zipWith (/)
+        ((\x' -> Map.findWithDefault 0 x' counts) <$> [f..l])
+        (zipWith (-) z x)
+    f = case o of
+          IgnoreOvers -> 1
+          IncludeOvers _ -> 0
+    l = case o of
+          IgnoreOvers -> length cs - 1
+          IncludeOvers _ -> length cs
+    w' = (/sum w) <$> w
+    x = case o of
+          IgnoreOvers -> cs
+          IncludeOvers outw ->
+            [Data.List.head cs - outw] <>
+            cs <>
+            [Data.List.last cs + outw]
+    z = drop 1 x
+
+
+-- | approx regular n-quantiles
+-- >>> regularQuantiles 4 [0..100]
+-- [0.0,24.75,50.0,75.25,100.0]
+--
+regularQuantiles :: Double -> [Double] -> [Double]
+regularQuantiles n = L.fold (quantileFold qs)
+  where
+    qs = ((1 / n) *) <$> [0 .. n]
+
+-- | one-pass approximate quantiles fold
+quantileFold :: [Double] -> L.Fold Double [Double]
+quantileFold qs = L.Fold step begin done
+  where
+    step x a = Data.TDigest.insert a x
+    begin = tdigest ([] :: [Double]) :: TDigest 25
+    done x = fromMaybe nan . (`quantile` compress x) <$> qs
+
+-- | take a specification of quantiles and make a Histogram
+-- >>> fromQuantiles [0,0.25,0.5,0.75,1] (regularQuantiles 4 [0..100])
+-- Histogram {cuts = [0.0,24.75,50.0,75.25,100.0], values = fromList [(1,0.25),(2,0.25),(3,0.25),(4,0.25)]}
+--
+fromQuantiles :: [Double] -> [Double] -> Histogram
+fromQuantiles qs xs = Histogram xs (Map.fromList $ zip [1..] (diffq qs))
+  where
+    diffq [] = []
+    diffq [_] = []
+    diffq (x:xs') = L.fold (L.Fold step (x,[]) (reverse . snd)) xs'
+    step (a0,xs') a = (a,(a-a0):xs')
+
+-- | normalize a histogram so that sum values = one
+-- >>> freq $ fill [0,50,100] [1..100]
+-- Histogram {cuts = [0.0,50.0,100.0], values = fromList [(1,0.5),(2,0.5)]}
+--
+freq :: Histogram -> Histogram
+freq (Histogram cs vs) = Histogram cs $ Map.map (* recip (sum vs)) vs
diff --git a/stack.yaml b/stack.yaml
new file mode 100644
--- /dev/null
+++ b/stack.yaml
@@ -0,0 +1,7 @@
+resolver: nightly-2017-12-29
+
+packages:
+- .
+
+extra-deps: []
+
diff --git a/test/test.hs b/test/test.hs
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--- /dev/null
+++ b/test/test.hs
@@ -0,0 +1,19 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# OPTIONS_GHC -Wall #-}
+
+module Main where
+
+import Protolude
+import Test.Tasty (TestTree, testGroup, defaultMain)
+import Test.DocTest
+
+main :: IO ()
+main = do
+    doctest ["src/NumHask/Histogram.hs"]
+    defaultMain tests
+
+tests :: TestTree
+tests =
+    testGroup ""
+    [
+    ]