diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright Suzumiya (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 Suzumiya 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/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,9 @@
+# light
+
+for detailed usage see source in test module
+
+[![BSD3 License](http://img.shields.io/badge/license-BSD3-brightgreen.svg)](https://tldrlegal.com/license/bsd-3-clause-license-%28revised%29)
+
+### Releases
+[![Hackage](https://img.shields.io/hackage/v/light.svg)](https://hackage.haskell.org/package/light)
+[![Dependencies](https://img.shields.io/hackage-deps/v/light.svg)](http://packdeps.haskellers.com/feed?needle=light)
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/light.cabal b/light.cabal
new file mode 100644
--- /dev/null
+++ b/light.cabal
@@ -0,0 +1,41 @@
+name:                light
+version:             0.1.0.0
+synopsis:            a simple physics engine
+description:         A simple physics engine(dynamics only) with collision dection
+homepage:            https://github.com/suzumiyasmith/light#readme
+license:             BSD3
+license-file:        LICENSE
+author:              Suzumiya
+maintainer:          suzumiyasmith@gmail.com
+copyright:           Copyright: (c) 2017 Suzumiya
+category:            Physics
+build-type:          Simple
+extra-source-files:  README.md
+cabal-version:       >=1.10
+
+library
+  hs-source-dirs:      src
+  exposed-modules:     Physics.Light
+  build-depends:       base >= 4.7 && < 5
+                     , linear >= 1.20 && < 2
+                     , gjk2d >= 0.1 && < 1
+                     , containers >= 0.5 && < 1
+                     , lens >= 4 && < 5
+                     , mtl >= 2.2 && < 3
+  default-language:    Haskell2010
+
+test-suite light-test
+  type:                exitcode-stdio-1.0
+  hs-source-dirs:      test
+  main-is:             Spec.hs
+  build-depends:       base
+                     , light
+                     , linear
+                     , lens
+                     , containers
+  ghc-options:         -threaded -rtsopts -with-rtsopts=-N
+  default-language:    Haskell2010
+
+source-repository head
+  type:     git
+  location: https://github.com/suzumiyasmith/light
diff --git a/src/Physics/Light.hs b/src/Physics/Light.hs
new file mode 100644
--- /dev/null
+++ b/src/Physics/Light.hs
@@ -0,0 +1,84 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+module Physics.Light where
+
+import GJK
+
+import Control.Arrow
+import Control.Lens
+import Control.Monad.Writer.Lazy
+import Data.Fixed
+import Data.Function
+import qualified Data.IntMap.Lazy as IM
+import Data.List
+import Linear
+
+data Object2D = Object2D
+  { _position :: V3 Double
+  , _velocity :: V3 Double
+  , _acceleration :: V3 Double
+  , _shape :: [Convex]
+  }
+
+makeLenses ''Object2D
+
+instance Show Object2D where
+  show o = show (o ^. position, o ^. velocity, o ^. acceleration)
+
+type PhysicsWorld = (IM.IntMap Object2D, Int)
+
+newPhysicsWorld :: PhysicsWorld
+newPhysicsWorld = (IM.empty, 0)
+
+addObject :: Object2D -> PhysicsWorld -> PhysicsWorld
+addObject o (w, fresh) = (IM.insert fresh o w, fresh + 1)
+
+addObjects :: [Object2D] -> PhysicsWorld -> PhysicsWorld
+addObjects (o:os) w = addObjects os $ addObject o w
+addObjects [] w = w
+
+update :: Double -> PhysicsWorld -> PhysicsWorld
+update dt = first (fmap w)
+  where
+    w :: Object2D -> Object2D
+    w o = o
+      & position %~ (+ o ^. velocity ^* dt)
+      & velocity %~ (+ o ^. acceleration ^* dt)
+      & position .  _z %~ (`mod'` (2 * pi))
+
+detectCollision :: PhysicsWorld -> [(Int, Int)]
+detectCollision (w, _) =
+  execWriter $ IM.traverseWithKey (\k o -> tell $ fmap ((,) k) (detect w k o)) w
+
+detect :: IM.IntMap Object2D -> Int -> Object2D -> [Int]
+detect w k1 o1 =
+  IM.keys $
+  IM.filterWithKey (\k2 o2 -> k1 < k2 && (shapeCollide `on` realShape) o1 o2) w
+  where
+    realShape o =
+      rotateConvex (o ^. position ^. _z) . moveConvex (o ^. position ^. _xy) <$>
+      o ^. shape
+
+shapeCollide :: [Convex] -> [Convex] -> Bool
+shapeCollide v1 v2 = and $ convexIntersect <$> v1 <*> v2
+
+ellipse :: Double -> Double -> Convex
+ellipse a b = Convex $ \d -> V2 (a * cos d) (b * sin d)
+
+circle :: Double -> Convex
+circle r = ellipse r r
+
+polygon :: [V2 Double] -> Convex
+polygon vs = Convex $ \d -> maximumBy (compare `on` dot (angle d)) vs
+
+moveConvex :: V2 Double -> Convex -> Convex
+moveConvex p s = Convex $ \d -> p + support s d
+
+rotateConvex :: Double -> Convex -> Convex
+rotateConvex r s = Convex $ \d -> rotateMatrix2D r !* support s d
+
+scaleConvex :: V2 Double -> Convex -> Convex
+scaleConvex c s = Convex $ \d -> scaled c !* support s d
+
+rotateMatrix2D :: Double -> V2 (V2 Double)
+rotateMatrix2D r = V2 (V2 (cos r) (-sin r)) (V2 (sin r) (cos r))
diff --git a/test/Spec.hs b/test/Spec.hs
new file mode 100644
--- /dev/null
+++ b/test/Spec.hs
@@ -0,0 +1,28 @@
+import Control.Lens
+import qualified Data.IntMap.Lazy as IM
+import Linear
+import Physics.Light
+
+main :: IO ()
+main = do
+  print $ detectCollision <$> (updateTest <$> [1 .. 1000] <*> [testWorld1, testWorld2])
+
+testShape1 = [circle 1, ellipse 0.5 3]
+
+testShape2 = polygon $ V2 <$> [-1, 1] <*> [-1, 1]
+
+o1 = Object2D 0 (V3 0 0 1) 0 testShape1
+
+o2 = Object2D (V3 1.5 0 0) (V3 0 0 0) 0 [testShape2]
+
+o3 = Object2D (V3 (-1.5) 0 0) (V3 0 0 0) 0 [testShape2]
+
+o4 = Object2D (V3 (-1.5) 0 0) (V3 1 0 0) 0 [testShape2]
+
+testWorld1 = newPhysicsWorld & addObjects [o1, o2, o3]
+testWorld2 = newPhysicsWorld & addObjects [o1, o3, o4]
+
+
+updateTest :: Int -> PhysicsWorld -> PhysicsWorld
+updateTest 0 w = w
+updateTest n w = update 0.1 $ updateTest (n - 1) w