(|+++|) :: [CornerPoints] -> [CornerPoints] -> [CornerPoints]
c1 |+++| c2 = zipWith (+++) c1 c2
(|+++|) :: [CornerPoints] -> [CornerPoints] -> [CornerPoints]
c1 |+++| c2 = zipWith (+++) c1 c2
c1 |+++| c2 = zipWith (+++) c1 c2