diff --git a/Visibility/Array.hs b/Visibility/Array.hs
deleted file mode 100644
--- a/Visibility/Array.hs
+++ /dev/null
@@ -1,7 +0,0 @@
-
-module Array
-	( Array
-	, module Data.Vector.Unboxed)
-where
-import Data.Vector.Unboxed
-type Array	= Vector
diff --git a/Visibility/Draw.hs b/Visibility/Draw.hs
--- a/Visibility/Draw.hs
+++ b/Visibility/Draw.hs
@@ -8,8 +8,7 @@
 import Geometry.Segment
 import Graphics.Gloss
 import Graphics.Gloss.Geometry.Line
-import qualified Array		as A
-import Array			(Array)
+import qualified Data.Vector.Unboxed	as V
 import Data.Maybe
 
 
@@ -60,7 +59,7 @@
 			
 			picSegsHit	= Pictures
 					$ [ Line [p1, p2]
-						| (_, p1, p2)	<- A.toList $ worldSegments world
+						| (_, p1, p2)	<- V.toList $ worldSegments world
 						, isJust $ intersectSegSeg p1 p2 pView pTarget ]
 	   	  in	Color red $ Pictures [picTarget, picLine, picSegsHit]
 
@@ -84,7 +83,7 @@
  = let	
 	visible pTarget	= not $ any isJust
 			$ map (\(_, p1, p2) -> intersectSegSeg pView pTarget p1 p2)
-			$ A.toList 
+			$ V.toList 
 			$ worldSegments world
 			
 	picGrid		= Pictures
@@ -105,11 +104,11 @@
 
 
 -- | Draw an array of segments.
-drawSegments :: Array Segment -> Picture
+drawSegments :: V.Vector Segment -> Picture
 drawSegments segments
 	= Pictures
 	$ map drawSegment
-	$ A.toList 
+	$ V.toList 
 	$ segments
 
 
diff --git a/Visibility/Geometry/Randomish.hs b/Visibility/Geometry/Randomish.hs
--- a/Visibility/Geometry/Randomish.hs
+++ b/Visibility/Geometry/Randomish.hs
@@ -6,10 +6,9 @@
 	, randomishDoubles)
 where
 import Data.Word
-import qualified Array				as A
 import qualified Data.Vector.Generic		as G
 import qualified Data.Vector.Unboxed.Mutable	as MV
-import Array					(Array)
+import qualified Data.Vector.Unboxed		as V
 
 -- | Some uniformly distributed points
 randomishPoints
@@ -17,13 +16,13 @@
 	-> Int			-- ^ number of points
 	-> Float		-- ^ minimum coordinate
 	-> Float		-- ^ maximum coordinate
-        -> Array (Float, Float)
+        -> V.Vector (Float, Float)
 
 randomishPoints seed' n pointMin pointMax
  = let  pts      = randomishFloats (n*2) pointMin pointMax seed'
         xs       = G.slice 0 n pts
         ys       = G.slice n n pts
-   in   A.zip xs ys
+   in   V.zip xs ys
 
 
 -- | Use the "minimal standard" Lehmer generator to quickly generate some random
@@ -40,7 +39,7 @@
 	-> Int 			-- Minumum value in output.
 	-> Int 			-- Maximum value in output.
 	-> Int 			-- Random seed.	
-	-> Array Int		-- Vector of random numbers.
+	-> V.Vector Int		-- Vector of random numbers.
 
 randomishInts !len !valMin' !valMax' !seed'
 	
@@ -85,7 +84,7 @@
 	-> Double		-- Minimum value in output
 	-> Double		-- Maximum value in output
 	-> Int			-- Random seed.
-	-> Array Double		-- Vector of randomish doubles.
+	-> V.Vector Double	-- Vector of randomish doubles.
 
 randomishDoubles !len !valMin !valMax !seed
  = let	range	= valMax - valMin
@@ -94,7 +93,7 @@
 	mxf	= fromIntegral mx
 	ints	= randomishInts len 0 mx seed
 	
-   in	A.map (\n -> valMin + (fromIntegral n / mxf) * range) ints
+   in	V.map (\n -> valMin + (fromIntegral n / mxf) * range) ints
 
 
 -- | Generate some randomish doubles with terrible statistical properties.
@@ -104,7 +103,7 @@
 	-> Float		-- Minimum value in output
 	-> Float		-- Maximum value in output
 	-> Int			-- Random seed.
-	-> Array Float		-- Vector of randomish doubles.
+	-> V.Vector Float	-- Vector of randomish doubles.
 
 randomishFloats !len !valMin !valMax !seed
  = let	range	= valMax - valMin
@@ -113,4 +112,4 @@
 	mxf	= fromIntegral mx
 	ints	= randomishInts len 0 mx seed
 	
-   in	A.map (\n -> valMin + (fromIntegral n / mxf) * range) ints
+   in	V.map (\n -> valMin + (fromIntegral n / mxf) * range) ints
diff --git a/Visibility/Geometry/Segment.hs b/Visibility/Geometry/Segment.hs
--- a/Visibility/Geometry/Segment.hs
+++ b/Visibility/Geometry/Segment.hs
@@ -10,8 +10,7 @@
 import Graphics.Gloss.Geometry.Line
 import Data.Maybe
 import Data.Function
-import qualified Array		as A
-import Array			(Array)
+import qualified Data.Vector.Unboxed	as V
 
 -- | A line segement in the 2D plane.
 type Segment	= (Int, (Float, Float), (Float, Float))
@@ -24,45 +23,45 @@
 	
 
 -- | Split segments that cross the line y = y0, for some y0.
-splitSegmentsOnY :: Float -> Array Segment -> Array Segment
+splitSegmentsOnY :: Float -> V.Vector Segment -> V.Vector Segment
 splitSegmentsOnY y0 segs
  = let	
 	-- TODO: we only need to know IF the seg crosse the line here,
 	--       not the actual intersection point. Do a faster test.
 	(segsCross, segsOther)
-		= A.unstablePartition 
+		= V.unstablePartition 
 			(\(_, p1, p2) -> isJust $ intersectSegHorzLine p1 p2 y0)
 			segs
 
 	-- TODO: going via lists here is bad.
-	splitCrossingSeg :: Segment -> Array Segment
+	splitCrossingSeg :: Segment -> V.Vector Segment
 	splitCrossingSeg (n, p1, p2)
 	 = let	Just pCross	= intersectSegHorzLine p1 p2 y0
-	   in	A.fromList [(n, p1, pCross), (n, pCross, p2)]
+	   in	V.fromList [(n, p1, pCross), (n, pCross, p2)]
 	
 	-- TODO: vector append requires a copy.	
-   in	segsOther A.++ (A.concat $ map splitCrossingSeg $ A.toList segsCross)
+   in	segsOther V.++ (V.concat $ map splitCrossingSeg $ V.toList segsCross)
 
 
 -- | Split segments that cross the line x = x0, for some x0.
-splitSegmentsOnX :: Float -> Array Segment -> Array Segment
+splitSegmentsOnX :: Float -> V.Vector Segment -> V.Vector Segment
 splitSegmentsOnX x0 segs
  = let	
 	-- TODO: we only need to know IF the seg crosse the line here,
 	--       not the actual intersection point. Do a faster test.
 	(segsCross, segsOther)
-		= A.unstablePartition 
+		= V.unstablePartition 
 			(\(_, p1, p2) -> isJust $ intersectSegVertLine p1 p2 x0)
 			segs
 
 	-- TODO: going via lists here is bad.
-	splitCrossingSeg :: Segment -> Array Segment
+	splitCrossingSeg :: Segment -> V.Vector Segment
 	splitCrossingSeg (n, p1, p2)
 	 = let	Just pCross	= intersectSegVertLine p1 p2 x0
-	   in	A.fromList [(n, p1, pCross), (n, pCross, p2)]
+	   in	V.fromList [(n, p1, pCross), (n, pCross, p2)]
 	
 	-- TODO: vector append requires a copy.	
-   in	segsOther A.++ (A.concat $ map splitCrossingSeg $ A.toList segsCross)
+   in	segsOther V.++ (V.concat $ map splitCrossingSeg $ V.toList segsCross)
 
 
 -- | Decide where to split the plane.
@@ -73,9 +72,9 @@
 --	 - the one closes to the middle of the field.
 --       - some combination of above.
 --
-chooseSplitX :: Array Segment -> Float
+chooseSplitX :: V.Vector Segment -> Float
 chooseSplitX segments
- = let	Just (_, (x1, _), _)	= segments A.!? (A.length segments `div` 2)
+ = let	Just (_, (x1, _), _)	= segments V.!? (V.length segments `div` 2)
    in	x1
 
 
diff --git a/Visibility/Interface.hs b/Visibility/Interface.hs
--- a/Visibility/Interface.hs
+++ b/Visibility/Interface.hs
@@ -1,4 +1,4 @@
-
+{-# LANGUAGE PatternGuards #-}
 module Interface
 	( handleInput
 	, stepState)
diff --git a/Visibility/World.hs b/Visibility/World.hs
--- a/Visibility/World.hs
+++ b/Visibility/World.hs
@@ -8,15 +8,14 @@
 import Graphics.Gloss
 import Geometry.Randomish
 import Geometry.Segment
-import qualified Array	as A
-import Array		(Array)
+import qualified Data.Vector.Unboxed as V
 
 
 -- We keep this unpacked so we can use unboxed vector.
 -- index, x1, y1, x2, y2
 data World 
 	= World
-	{ worldSegments	:: Array Segment }
+	{ worldSegments	:: V.Vector Segment }
 
 
 -- | Generate the initial world.
@@ -35,7 +34,7 @@
 	let makePoint n' (cX, cY) (dX, dY)
 			= (n', (cX, cY), (cX + dX, cY + dY))
 
-	let segs	= A.zipWith3 makePoint (A.enumFromTo 0 (n - 1)) centers deltas
+	let segs	= V.zipWith3 makePoint (V.enumFromTo 0 (n - 1)) centers deltas
 	
 	return $ World segs
 
@@ -44,7 +43,7 @@
 --   and split segements that cross the y=0 line.
 normaliseWorld :: Point -> World -> World 
 normaliseWorld (px, py) world
- = let	segments_trans	= A.map (translateSegment (-px) (-py)) 
+ = let	segments_trans	= V.map (translateSegment (-px) (-py)) 
 			$ worldSegments world
 			
 	segments_split	= splitSegmentsOnY 0 segments_trans
diff --git a/gloss-examples.cabal b/gloss-examples.cabal
--- a/gloss-examples.cabal
+++ b/gloss-examples.cabal
@@ -1,5 +1,5 @@
 Name:                gloss-examples
-Version:             1.3.0.1
+Version:             1.3.1.1
 License:             MIT
 License-file:        LICENSE
 Author:              Ben Lippmeier
@@ -101,7 +101,7 @@
   Build-depends: 
         base            == 4.*,
         gloss           == 1.3.*,
-        vector          >= 0.5 && < 0.8
+        vector          == 0.7.*
   Main-is: Main.hs
   other-modules: Cell World
   hs-source-dirs: Conway
@@ -119,9 +119,10 @@
 Executable gloss-visibility
   Build-depends: 
         base            == 4.*, 
-        gloss           == 1.3.*
+        gloss           == 1.3.*,
+        vector          == 0.7.*
   Main-is: Main.hs
-  other-modules: Array Draw Interface State World Geometry.Randomish Geometry.Segment
+  other-modules: Draw Interface State World Geometry.Randomish Geometry.Segment
   hs-source-dirs: Visibility 
   ghc-options: -O2