-- Lower-lefts
lls :: (Enum a, Num a) => a -> a -> [(a,a)]
lls cols rows = liftA2 (,)  [0 .. cols-2] [0 .. rows-2]
lls :: (Enum a, Num a) => a -> a -> [(a,a)]
lls cols rows = liftA2 (,)  [0 .. cols-2] [0 .. rows-2]
lls cols rows = liftA2 (,)  [0 .. cols-2] [0 .. rows-2]