From L33 onward, stone walls spawn from 8 anchor points around the map — one at each of the 4 corners (NE/NW/SE/SW) plus one on each of the 4 edges (N/S/W/E).
Every new wall always links to the previous wall from its anchor — chains snake inward, bend when direction changes, never break. Direction is picked at random from 3 inward options per anchor:
If a spawn would land out of bounds, the chain waits for an inward direction on the next cycle.
Per-player state (same as Swarm / Cryo Cloud) — your walls don't replicate to opponents, and theirs don't reach you.