merge (x:xs) (y:ys) | x < y = x : merge xs (y:ys) | x > y = y : merge (x:xs) ys | x == y = x : merge xs ys supermerge (x:[]) = x supermerge (x:y:ys) = supermerge $ (merge x y) : ys multiples x = map (*x) [1..] multiplesFromList x = supermerge $ map (multiples) x limbic's_challenge = multiplesFromList [2,3,5]