>>> tail [1, 2, 3] [2,3] >>> tail [1] [] >>> tail [] *** Exception: Prelude.tail: empty list
>>> reverse [] [] >>> reverse [42] [42] >>> reverse [2,5,7] [7,5,2] >>> reverse [1..] * Hangs forever *
>>> init [1, 2, 3] [1,2] >>> init [1] [] >>> init [] *** Exception: Prelude.init: empty list
>>> cycle [] *** Exception: Prelude.cycle: empty list >>> take 20 $ cycle [42] [42,42,42,42,42,42,42,42,42,42... >>> take 20 $ cycle [2, 5, 7] [2,5,7,2,5,7,2,5,7,2,5,7...