The contact/girth law, live. The left rim is geometrically seeded — every other cell is blind until a neighbour's quarter-turn wakes it. Watch vision propagate inward.
Drive
F1.0
F = 1 floor, ×up to 8. Low F: cascade crawls or stalls. High F: a single quarter-turn catches and it sweeps.
Grid
size28
Run
Legend
blind (not yet rotated) right-chiral — expanding, time forward left-chiral — contracting, time reversed (girth flipped it)