link to the shiny thing
This is completely deterministic. All the patterns are dictated by me, off the top of my head. It's eight layers of transformation compounded. Flash's symbolic model makes this very easy to do; it was quick.
For the statistically-minded, I think it repeats if you watch it for about 11 billion frames (~7000 days). The file is 12k.
This is more of a test than anything else... I think it could look a lot more interesting.