Ugly -> nicer?

Unzip

class Functor f => Unzip f where
  unfzip ::
    f (a, b) 
    -> (f a, f b)

  unfzip3 ::
    f (a, b, c)
    -> (f a, f b, f c)
  unfzip3 x =
    let (a, bc) = unfzip (fmap (\(a', b', c') -> (a', (b', c'))) x)
        (b, c) = unfzip bc
    in (a, b, c)

  unfzip4 ::
    f (a, b, c, d)
    -> (f a, f b, f c, f d)
  unfzip4 x =
    let (a, b, cd) = unfzip3 (fmap (\(a', b', c', d') -> (a', b', (c', d'))) x)
        (c, d) = unfzip cd
    in (a, b, c, d)