data AB = A | B

render ab =
    let red' = case ab of
                  A -> 1.0
                  B -> 0.0
        frame = FrameBuffer ((colorImage1 (V4 red' 0.0 0.4 1.0)))
    in ScreenOut frame

data Out = Out (AB -> Output)

out = Out render

main = let
  Out o = out
  in o A