A 3-state firing automaton that grows shifting patterns.
This is the whole thing. Phluxel runs it on every cell, every step — the animation is what happens when you repeat it.
R > 0 ? [255,0,90,255] : (G > 0 ? [255,0,0,0] : ({COUNTNZ, MOORE.R} == 2 ? [255,255,255,255] : [255,0,0,0]))
Paste it into the Rule Editor, or pick Brian's Brain from the template list and skip the typing.
Phluxel runs in the browser as a demo, and the free desktop edition has every feature with a watermark on exports.
Open the browser demo Download free (Windows) Wishlist on Steam