Coil

Coil is a minimalist one-button puzzle by Hakim El Hattab, the creator of Loop. On each level a dot patrols a grid; the whole board advances one step whenever you place or remove a wall.

The rule is elegantly counterintuitive: draw a loop to trap the dot and you win, but if the dot escapes into open space you lose. There is no character to move and no timer to beat - the board is entirely deterministic, so a level is always solvable and every move you make is a commitment. Rendered with a subtle particle trail on canvas.

How to Play

1. Click a cell to add a wall, click it again to remove it.
2. Enclose the patrolling dot in a closed circuit.
3. The board advances one step after every edit, so plan two moves at a time.
4. Clear the level to unlock the next.

Controls

• Mouse / touch - click a cell to toggle a wall

Tips

The dot moves the instant you finish a wall segment. Work backwards from the dot's next position and place the closing wall one step before it arrives, not on the step it arrives.

Open Source & License

MIT License It is integrated here as a self-hosted build, running entirely in your browser from /games/coil/ with no external services.

• Original source: https://github.com/leereilly/Coil