haskell brain damage cancer invades scheme*

http://blog.racket-lang.org/2007/11/getting-rid-of-set-car-and-set-cdr.html

(* depr derp we're not "scheme" anymore... i know)

>>15
If you're able to declare and use many types, it's multityped. If you're stuck with just one type, its unityped. For example, you'd be hard pressed to declare two different types in Python or Ruby.