Yeah, sorry, some of the patterns can get a bit flashy, especially when they have rules like all black pixels -> white + all white pixels -> black.

If it helps, the slider down the bottom controls the speed. Or here are a few patterns that are certified non-flashy:

Expanding squares: https://demos.samgentle.com/automata-by-example/?1=1a&26=10&...

Diamond: https://demos.samgentle.com/automata-by-example/?2=10&49=10&...

Rule 30: https://demos.samgentle.com/automata-by-example/?1=10&2=10&4...

It's very cool, but you should put an actual red-letter epilepsy warning at the top of the page if you want to keep those flashy patterns. Or else don't offer the faster rates.

This could definitely trigger some of the epileptics I've known.

That's a good thought, thanks. I've added an epilepsy warning that triggers when you have both full-white and full-black rules enabled: https://demos.samgentle.com/automata-by-example/?0=10&1ff=10

Bravo, well done.

Genuine question, do people not run some kind of screen filter software if they have that kind of epilepsy? It seems like quite an oversight, and I don't think it'd be that hard to implement. Even just something that applies a 1-2 second low pass filter to any pixels that see a large jump in brightness.