How to play Lights Out

Lights Out is a wonderfully compact logic puzzle played on a 5×5 grid of lit and unlit cells. The catch that makes it so absorbing: you can never toggle just one light. Every press flips a small cross of cells at once, so each move undoes a little of what you've already done. Turning the whole board off feels impossible at first — then suddenly it clicks.

Goal

Switch off every light. The puzzle begins with some cells glowing and the rest dark, and you win the instant the entire 5×5 grid is dark.

How moves work

Tap or click any cell and it toggles five lights: the cell you pressed plus its four orthogonal neighbours — the ones directly above, below, left, and right. Cells on an edge or in a corner simply toggle fewer neighbours, since there's nothing off the board to flip. Pressing the same cell twice returns those lights to where they started, which is the key insight behind solving it: order doesn't matter, only whether each cell is pressed an odd or even number of times.

Strategy

The reliable technique is called "chasing the lights." Work strictly from the top row downward: whenever a light in a row is still on, press the cell directly beneath it in the next row to clear it. Repeat all the way down and you'll extinguish every light except possibly some stuck in the bottom row. The exact pattern left on that bottom row tells you which cells in the very top row you should have pressed first; press them, chase down again, and the board goes dark.

Good to know

• Every puzzle here is built by applying random presses to an all-dark board, so a solution is always guaranteed to exist.
• There's no penalty for experimenting — toggle freely, and remember that pressing a cell twice cancels it out.
• With practice you'll start to recognise the bottom-row patterns by sight and finish puzzles in just a handful of confident moves.