Lights Out

Lights Out is one of the great minimalist puzzles. The board is a 5×5 grid of lit squares, and your goal is to turn every single light off. The twist: tapping any square flips not just that square but also its four neighbors. What seems like a tap-anywhere puzzle quickly reveals itself as a tightly constrained logic problem with exactly one solution.

Tap any square. That square and its direct neighbors (up, down, left, right) all toggle on/off. Corner squares affect 3 neighbors; edge squares affect 4; interior squares affect 5. There are no moves counter and no time limit — just keep tapping until the board is dark.

Try the "chase the lights" technique: in row 1, tap exactly above any lit square to clear row 1. Repeat for rows 2 through 4. By row 5, the pattern of remaining lights tells you what to tap in row 1 to clear everything. Some configurations are unsolvable without restarting — if you're stuck after many moves, hit restart and try a different opening.

Lights Out is a perfect puzzle: rules you can teach in 10 seconds, depth that mathematicians have spent papers analyzing. Every level has exactly one minimal solution, and finding it always feels earned. The 5×5 grid means each puzzle is fast — under two minutes once you know the technique — making it ideal for quick mental breaks.

For puzzle purists. If you enjoy Sudoku, Picross, or any game where the rules are simple but mastery takes real thought, Lights Out will hook you. No reflexes, no luck, just pure logic.