Here is my first real program in Haskell. How come you started out with playing around with FRP libraries right away? It's a rather peculiar choice, I'd say.
In fact, I'm not fully responsible because it's just an adapted version of a Tetris Creighton Hogg had written for Reactive/GLUT. As the first version, it's a very simple game (no levels, no points ...) but it's playable ! It's an interesting exercise, and quite a nice job from someone who considers themselves a beginner.
One thing I don't really understand is why you packed up those applicative combinators in a SignalMonad, i.e. the reason behind flat and sf_sa. You have much more freedom in using them as they are, since they can appear inside any expression. For instance, you could just say the following in the let declaration: sfall = (uncurry . fall) <$> randomBehavior seed sid = pure id Or even better, since both sfall and sid are created by pure combinators, you don't even need to name them if they are used only once anyway: autumn = ifte metronome ((uncurry . fall) <$> randomBehavior seed) (pure id) Another thing, which is really a matter of taste, is that you seem to like point-free style acrobatics. I don't think it's always the best choice, especially if you are to share code with others, since most people grok code with explicit parameters easier than magic involving flip and const and (un)curry and the like, except for the obvious cases of composing a chain of operations, where dropping arguments feels quite natural. For instance, the definition of f_a looks problematic to me because of these concerns. Gergely -- http://www.fastmail.fm - Same, same, but different...