diff --git a/src/Geometry/Delaunay/CDelaunay.hs b/src/Geometry/Delaunay/CDelaunay.hs
index 7208241..24b7244 100644
--- a/src/Geometry/Delaunay/CDelaunay.hs
+++ b/src/Geometry/Delaunay/CDelaunay.hs
@@ -6,17 +6,23 @@ module Geometry.Delaunay.CDelaunay
   , c_tessellation 
   )
   where
-import           Control.Monad              ((<$!>))
+import           Control.Monad              ( (<$!>) )
 import qualified Data.HashMap.Strict.InsOrd as H
-import           Data.IntMap.Strict         (fromAscList, (!))
+import           Data.IntMap.Strict         ( fromAscList, (!) )
 import qualified Data.IntSet                as IS
-import           Data.List
-import           Data.Maybe
-import           Data.Tuple.Extra           (both, fst3, snd3, thd3, (&&&))
-import           Geometry.Delaunay.Types
-import           Foreign
-import           Foreign.C.Types
-import           Geometry.Qhull.Types
+import           Data.List                  ( findIndex )
+import           Data.Maybe                 ( fromJust, isJust )
+import           Data.Tuple.Extra           ( both, fst3, snd3, thd3, (&&&) )
+import           Geometry.Delaunay.Types    ( Tessellation(..),
+                                              Tile(..),
+                                              TileFacet(..),
+                                              Simplex(..),
+                                              Site(..) )
+import           Foreign  ( Ptr,
+                            Storable(pokeByteOff, poke, peek, alignment, sizeOf, peekByteOff),
+                            peekArray )
+import           Foreign.C.Types            ( CInt, CDouble(..), CUInt(..) )
+import           Geometry.Qhull.Types       ( Family(Family, None), IndexPair(Pair) )
 
 data CSite = CSite {
     __id             :: CUInt
diff --git a/src/Geometry/Delaunay/Delaunay.hs b/src/Geometry/Delaunay/Delaunay.hs
index aa846fa..5de8863 100644
--- a/src/Geometry/Delaunay/Delaunay.hs
+++ b/src/Geometry/Delaunay/Delaunay.hs
@@ -10,19 +10,27 @@ module Geometry.Delaunay.Delaunay
   , facetCenters'
     ) 
   where
-import           Control.Monad         (unless, when)
-import           Data.IntMap.Strict    (IntMap)
-import qualified Data.IntMap.Strict    as IM
-import qualified Data.IntSet           as IS
-import           Data.List.Unique      (allUnique)
-import           Data.Maybe
-import           Geometry.Delaunay.CDelaunay
-import           Geometry.Delaunay.Types
-import           Foreign.C.Types
-import           Foreign.Marshal.Alloc (free, mallocBytes)
-import           Foreign.Marshal.Array (pokeArray)
-import           Foreign.Storable      (peek, sizeOf)
-import           Geometry.Qhull.Types
+import           Control.Monad               ( unless, when )
+import           Data.IntMap.Strict          ( IntMap )
+import qualified Data.IntMap.Strict          as IM
+import qualified Data.IntSet                 as IS
+import           Data.List.Unique            ( allUnique )
+import           Data.Maybe                  ( fromMaybe )
+import           Geometry.Delaunay.CDelaunay ( c_tessellation
+                                             , cTessellationToTessellation 
+                                             )
+import           Geometry.Delaunay.Types     ( Tessellation(_tilefacets, _sites, _tiles),
+                                               Tile,
+                                               TileFacet(_facetOf),
+                                               Site(_neighfacetsIds) )
+import           Foreign.C.Types             ( CDouble, CUInt )
+import           Foreign.Marshal.Alloc       ( free, mallocBytes )
+import           Foreign.Marshal.Array       ( pokeArray )
+import           Foreign.Storable            ( peek, sizeOf )
+import           Geometry.Qhull.Types        ( HasCenter(_center), 
+                                               HasFamily(_family), 
+                                               Family, 
+                                               Index )
 
 delaunay :: [[Double]]     -- ^ sites (vertex coordinates)
          -> Bool           -- ^ whether to add a point at infinity
diff --git a/src/Geometry/Delaunay/Types.hs b/src/Geometry/Delaunay/Types.hs
index 57b39b9..f40c77b 100644
--- a/src/Geometry/Delaunay/Types.hs
+++ b/src/Geometry/Delaunay/Types.hs
@@ -7,10 +7,19 @@ module Geometry.Delaunay.Types
   , Tessellation (..)
   )
   where
-import           Data.IntMap.Strict (IntMap)
-import qualified Data.IntMap.Strict as IM
-import           Data.IntSet        (IntSet)
-import           Geometry.Qhull.Types
+import           Data.IntMap.Strict   ( IntMap )
+import qualified Data.IntMap.Strict    as IM
+import           Data.IntSet          ( IntSet )
+import           Geometry.Qhull.Types ( HasCenter(..),
+                                        HasVolume(..),
+                                        HasEdges(..),
+                                        HasVertices(..),
+                                        HasNormal(..),
+                                        HasFamily(..),
+                                        Family,
+                                        EdgeMap,
+                                        IndexSet,
+                                        IndexMap )
 
 data Site = Site {
     _point          :: [Double]
diff --git a/src/Geometry/Qhull/Shared.hs b/src/Geometry/Qhull/Shared.hs
index 2258f21..1fb8d0c 100644
--- a/src/Geometry/Qhull/Shared.hs
+++ b/src/Geometry/Qhull/Shared.hs
@@ -15,8 +15,12 @@ module Geometry.Qhull.Shared
   where
 import qualified Data.HashMap.Strict.InsOrd as H
 import qualified Data.IntMap.Strict         as IM
-import           Data.Maybe
-import           Geometry.Qhull.Types
+import           Data.Maybe                 ( fromJust )
+import           Geometry.Qhull.Types       ( HasEdges(..),
+                                              HasVertices(..),
+                                              Family(Family),
+                                              IndexPair(..),
+                                              Index )
 
 -- | whether two families are the same
 sameFamily :: Family -> Family -> Bool
diff --git a/src/Geometry/Qhull/Types.hs b/src/Geometry/Qhull/Types.hs
index 87ba63c..5d1d5fb 100644
--- a/src/Geometry/Qhull/Types.hs
+++ b/src/Geometry/Qhull/Types.hs
@@ -14,10 +14,10 @@ module Geometry.Qhull.Types
   , HasVolume (..)
   )
   where
-import           Data.Hashable
-import           Data.HashMap.Strict.InsOrd (InsOrdHashMap)
-import           Data.IntMap.Strict         (IntMap)
-import           Data.IntSet                (IntSet)
+import           Data.Hashable              ( Hashable(hashWithSalt) )
+import           Data.HashMap.Strict.InsOrd ( InsOrdHashMap )
+import           Data.IntMap.Strict         ( IntMap )
+import           Data.IntSet                ( IntSet )
 
 type Index = Int
 type IndexMap = IntMap