Your favourite Haskell Haikus

Post your favourite Haskell Haikus! I'll start:

Prelude> foldl (+) 0 [1..100000000]
<interactive>: out of memory

Prelude> foldr (+) 0 [1..100000000]
<interactive>: out of memory

Prelude> id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id id 1
<interactive>: out of memory

>>11
That might be difficult. If you know you can do it efficiently, fine. But computing fibs in reverse for some huge number isn't going to fix foldr. Or maybe it will, Haskell performance is capricious business.