Lights Out

Lights Out is a compact logic puzzle where one tap changes several cells. Your goal is to turn off every yellow light on a 5 × 5 board. Selecting a cell flips that cell and its neighbors above, below, left and right. Lit cells turn off and dark cells turn on. Diagonal neighbors do not change, and edge cells have fewer neighbors.

A move that looks helpful locally may complicate the whole board. Switching off one central light can switch on four others. Instead of chasing the brightest area, consider how moves overlap. Pressing the same cell twice cancels those two moves. The order of moves does not change their final combined effect; what matters is which cells are pressed an odd number of times.

Each level is prepared by making valid moves on an all-dark board, so the starting position is solvable. Later levels use more setup moves, although that does not guarantee an increasing minimum solution length. Hint outlines a cell belonging to a solution of the current board. Undo reverses your most recent move.

A useful experiment is to work from the top row downward, using a cell below an unwanted light to switch it off. The final row shows the consequences of your earlier choices. There is no countdown. This edition's code and light design were created for TOFTI, without in-game advertising or third-party tracking code. Refreshing the page resets level progress.

How to play

Click or tap a light. That cell and its four straight neighbors flip together. Finish with no yellow lights remaining. Use arrow keys to move between cells and Enter or Space to make a move.

Undo reverses the last move and reduces the move counter. Hint outlines one move in a valid solution; selecting it still counts as an ordinary move. The hint is not a guarantee of the shortest possible solution.

When all lights are off, Next level appears. New game returns to level one. First try pressing the same cell twice to see the cancellation rule, then compare the overlapping effects of two neighboring moves.