[Haskell-cafe] Help with IO and randomR

I'm writing some code to generate a dither (=noise) signal. I'm trying to generate an infinite series of noise with triangular distribution but my code hangs into an infinite loop. The problem is that I'm not very good with Haskell IO yet and I can't figure out how to write this piece of IO code without it looping infinitely. So, in short, how do I do this without getting into an infinite loop: tpdfs :: (Int, Int) -> IO [Int] tpdfs (low, high) = do first <- getStdRandom (randomR (low, high)) second <- getStdRandom (randomR (low, high)) let r = (first + second) `div` 2 rest <- tpdfs (low, high) return (r : rest) Caller site: do nums <- tpdfs (2, 12) let ns = take 7 nums Niko