diff --git a/07/solution.hs b/07/solution.hs
index 11c91f5..e34af05 100644
--- a/07/solution.hs
+++ b/07/solution.hs
@@ -9,9 +9,6 @@ traceOut x = traceShow x x
 (***) :: (a -> a') -> (b -> b') -> (a, b) -> (a', b')
 (f *** g) (x, y) = (f x, g y)
 
-(****) :: (a -> a' -> a'') -> (b -> b' -> b'') -> (a, b) -> (a', b') -> (a'', b'')
-(f **** g) (p, q) (r, s) = (f p r, g q s)
-
 addFirst :: [[a]] -> a -> [[a]]
 addFirst [] x = [[x]]
 addFirst (y:ys) x = (x : y) : ys