I like all the rulesets, however I really think the developer should look into more efficient algorithm sets, or possibly making this multithreaded because it runs exceptionally slow. I've written quite a few of these in my time and the best way to make it more interesting is to speed it up. I also recommend allowing color gradients and even additive composite cells. Look at the buddahbrot fractal to see what I mean. There is a paid version of this app too, don't get sucker in when you can get it for free! In the free version it is much faster, but I recommend iteration skipping to add to the effect