Lights Out

Lights Out is a pure logic puzzle on a 5×5 grid. Clicking a cell toggles it and its four orthogonal neighbours, and the goal is to leave the board completely dark.

The board is always generated by random clicks from the solved state, which guarantees a solution exists. The challenge is finding a short sequence rather than wandering around the grid flipping lights back on.

There is no timer, only a move counter and a local best. It is a good puzzle to solve slowly with a cup of coffee.

How to play Lights Out

• Click any cell to toggle it and the four cells directly above, below, left and right.
• Keep clicking until every light is off.
• The move counter tracks how many clicks you used.
• New Board generates a fresh solvable puzzle.

Tips & strategy

Lights Out is linear algebra disguised as a light switch. The key insight is that clicking a cell twice is the same as never clicking it.

• Work from the top row downward. Once a row is correct, use the row below it to fix the remaining lights.
• Never click the same cell twice — the second click undoes the first and wastes two moves.
• Plan the whole cross before clicking. Each move changes five cells, including ones you may have already fixed.
• If the board looks scrambled, reset your mental model and work row by row instead of chasing individual lights.
• The centre cell is the most expensive move because it touches four neighbours; save it for last.
• Compare your move count with the best score — a 5×5 board usually has a solution under 15 moves.

Controls

Questions