Overview
filling-lines asks you to cover a board with continuous lines that don’t collide, a puzzle about route economy and corner respect. You don’t paint chaos; you compose flow. The trick is anchoring a backbone through straights, then threading smaller lines along edges to complete coverage without closing corridors. Corners require slower entries, and bends are expensive—use them to unlock future straights rather than burn space. The UI stays crisp so planning reads like drafting: ghost paths hint potential, subtle highlights mark adjacency. A satisfying cadence emerges: backbone first, perimeter routes second, final trims last. Misses teach—collisions signal poor trunk protection, dead pockets mean you sealed a corridor too soon, and jagged paths indicate inputs were too aggressive. Correction is gentle: undo, reopen space, rethread, continue. The board finishes looking clean, like a map you traced with care.