Some nice open source code here http://wonderfl.net
two of my favourites so far… http://wonderfl.net/code/fd77117130bc4a82c686afa7c3a2fa19a3b8e0fa
and http://wonderfl.net/code/ce881d62961c249592080a882606a02275de30d1
(give them a few seconds to load before clicking the play button)