12 rooms on a side
Twelve is also the daily size. Wrong branches start to cost real time.
Same room count as Medium and Timed. The daily board locks the seed to the UTC date; this page opens a fresh seed each time. Fog and keys both work cleanly at twelve.
The number is rooms, not pixels. Walls sit between rooms, so the drawing is 25 tiles across. Start is top-left; exit is bottom-right. Same seed, size, and mode rebuild the same corridors.
How to walk it
Arrows and swipe take a whole corridor and stop at the next fork. Yellow marks where you moved — not a solved path. Hint draws one solid arrow; Peek flashes the shortest route. Either leaves that run off local Marks.
Also: all room counts, make desk, print this size, right-hand rule.