Diffusion

Colors spread and blend like heat through the grid.

Color & Effects · a single painted seed plus one Phlux rule, simulated live · 96×96 grid

The rule that makes it move

This is the whole thing. Phluxel runs it on every cell, every step — the animation is what happens when you repeat it.

R = R * 0.8 + (N.R + S.R + E.R + W.R) * 0.05; G = G * 0.8 + (N.G + S.G + E.G + W.G) * 0.05; B = B * 0.8 + (N.B + S.B + E.B + W.B) * 0.05

Paste it into the Rule Editor, or pick Diffusion from the template list and skip the typing.

Make it yourself

1. Open Phluxel and start a new field, or click Diffusion in the starter gallery to get this exact setup.
2. Leave Wrap edges off — this one is meant to have real borders.
3. Press play. Change colours or numbers while it runs; you never have to stop and restart.
4. Export a seamless loop as GIF, APNG, MP4, a PNG sequence, or a sprite sheet.