diff --git a/Internal/Karel.hs b/Internal/Karel.hs
index 43092a7..82cfec5 100644
--- a/Internal/Karel.hs
+++ b/Internal/Karel.hs
@@ -15,10 +15,6 @@ data Karel = Karel
   }
   deriving (Eq)
 
-xor :: Bool -> Bool -> Bool
-xor True a = not a
-xor False a = a
-
 getHeader :: Karel -> String
 getHeader karel = unlines [
     printf " %8s   %s  %s  %s" "POSITION" "FACING" "BEEP-BAG" "BEEP-POS",
@@ -73,7 +69,7 @@ mapWall karel x y = leftPart <> rightPart
       | northWall && wallEnds && verticalWall = "-|"
       | wallEnds || (northWall && eastWallAbove) = "-+"
       | northWall = "--"
-      | (verticalWall && northWallOnRight) || (eastWall `xor` eastWallAbove) = " +"
+      | (verticalWall && northWallOnRight) || (eastWall /= eastWallAbove) = " +"
       | verticalWall = " |"
       | otherwise = "  "