interleave :: [a] -> [a] -> [a]
pinterleave :: P a -> P a -> P a

Interleave elements from two patterns.  If one pattern ends the other
pattern continues until it also ends.

> import Sound.SC3.Lang.Pattern.List

> let { p = pseq [1, 2, 3] 3
>     ; q = pseq [4, 5, 6, 7] 2 }
> in pinterleave p q

> ptake 10 (pinterleave (pcycle 1) (pcycle 2))

> ptake 10 (pinterleave (pwhite "x" 1 9) (pseries 10 1 5))