Click anywhere: the next colour spreads out from that unit, each unit starting later the further away it is.
Two flaps per unit, so a cell flips once when it is born or dies. Click a unit to toggle its cell.
Overlapping waves on a drum of twelve hues. Units take the shorter way round the drum, so the bands flow.
Each unit flips between off and on; the painter colours lit units by row.
A 3 × 5 pixel font. Each second only the pixels that change flip.