diff --git a/src/Data/Geometry/YX.hs b/src/Data/Geometry/YX.hs
--- a/src/Data/Geometry/YX.hs
+++ b/src/Data/Geometry/YX.hs
@@ -39,8 +39,11 @@
 import Data.List (groupBy)
 
 -- | A 2D coordinate.
---
-data YX = YX { y :: !Int, x :: !Int } deriving (Eq, Ord, Show)
+data YX
+  = YX
+    { y :: {-# UNPACK #-} !Int -- ^ Y-axis coordinate.
+    , x :: {-# UNPACK #-} !Int -- ^ X-axis coordinate.
+    } deriving (Eq, Ord, Show)
 
 lift1 :: (Int -> Int) -> YX -> YX
 lift1 f (YX y1 x1) = YX (f y1) (f x1)
diff --git a/yx.cabal b/yx.cabal
--- a/yx.cabal
+++ b/yx.cabal
@@ -1,5 +1,5 @@
 name:                yx
-version:             0.0.4.2
+version:             0.0.4.3
 synopsis:            Row-major coordinates
 description:         A minimal library for handling 2D coordinates.
 homepage:            https://github.com/mtth/yx