| z <- [0..zsize]]
where
zsize = (length m) - 1
- ysize = (length $ head m)- 1
- xsize = (length $ head $ head m) - 1
+ ysize = length (head m) - 1
+ xsize = length (head $ head m) - 1
-- | Takes a list, and returns True if its elements are pairwise
-- equal. Returns False otherwise.