And yet another short, functional solution: pairs = (>>= \ ~(x:xs) -> map ((,) x) xs) . init . tails EDIT: Or as a list comprehension: pairs xs = con

And yet another short, functional solution: pairs = (>>= \ ~(x:xs) -> map ((,) x) xs) . init . tails EDIT: Or as a list comprehension: pairs xs = concat [map ((,) h) t | (h:t) <- tails xs]