SKS /= I
s k s :: (a -> b -> c) -> a -> b -> c s k k :: a -> a
s f g x = f x (g x) k x y = x -- s :: (a -> b -> c) -> (a -> b) -> a -> c -- k :: a -> b -> a -- s: c == a -- s k :: (a -> b) -> a -> a -- s k: a == (a -> b -> c), b == ((a -> b) -> a -> c) -- s k s :: (a -> b -> c) -> a -> b -> c