Sorry. ^^' Didn't mean to be confusing.
Wikipedia might be able to explain it better than I can:
http://en.wikipedia.org/wiki/Op_ArtIt's stuff like
this, or
this, or
this.. or here's a site with a bunch of examples:
http://www.chadderton.com/images/akitaoka/opart-e.html (keep in mind, it may give you a headache if you're sensitive to stuff like this). Not really asking you to do anything like that, it just seems like something you might be interested in, if you enjoy doing those fractal sort of things.
Scintillation is when something like that is made up of contrasting colours, usually complementary ones (blue/orange, red/green, yellow/purple), and when you look at it, it almost makes your vision "vibrate" in a way. Not sure how else to explain it.
Victor Vasarely is a fairly well known creator of op art, you could look up some of his stuff too, just using Google, if you want.
Hope that's a little more clear for you. Just something I thought about when I saw the work you did. You're free to ignore me and do whatever you want, by all means.