ike `shuffle` but randomly selects from the parts
of `p` instead of making permutations.
For example, `scramble 3 "a b c"` will randomly select 3 parts from
`"a"` `"b"` and `"c"`, possibly repeating a single part.
-}
scramble :: Pattern Int -> Pattern a -> Pattern a
scramble = tParam _scramble

_scramble :: Int -> Pa
scramble :: Pattern Int -> Pattern a -> Pattern a
scramble = tParam _scramble
scramble = tParam _scramble