 Rotate point 270° clockwise about the origin
rotatePoint270c :: (Num a) => Point a -> Point a
rotatePoint270c (P x y) =
    P (-y) x

-
rotatePoint270c :: (Num a) => Point a -> Point a
rotatePoint270c (P x y) =
    P (-y) x
rotatePoint270c (P x y) =
    P (-y) x