Based on Cliff Biffle’s tremendously cool rust+webassembly series, and continuing to riff on cellular automata, this uses three states instead of two. The extra state takes us from 23 = 8 “parent rules” and 28 = 256 rulesets, up to 33 = 27 “parent rules” with 327 = 7,625,597,484,987 rulesets!
I found that things got, visually, a little muddled with three colors, so I have it start out zoomed in on each one, so you can see the detail and patterns better, and then zoom out as it finishes calculating the image.
I also switched from treating the borders as “background color” to having them wrap horizontally. I think this makes it a little easier to see what’s happening on the rulesets that produce horizontal striping.