Coilu

Coilu is a numbers-and-logic grid puzzle game where every move is a deduction. Fill each cage so rows, columns, and arithmetic targets all line up — no guessing, no luck, just clean reasoning from start to finish. Choose from four difficulty levels — Easy through Expert — and grid sizes from 3x3 to 6x6. Every puzzle is generated on-device with a guaranteed unique solution, so you never run out of fresh challenges. Use pencil marks to track candidates, undo any move, and let live conflict highlighting catch errors the instant they appear. The Learn section walks you through key solving techniques with interactive demos that reveal each deduction step by step. Every puzzle carries a seed code you can save or share — re-enter it anytime to replay the exact same grid. Track your best times across every size and difficulty, and build a Trophy Wall to mark your hardest conquests. Coilu runs entirely offline. No accounts, no subscriptions, no ads — just the puzzle.