How to play

Some of the lights are on (yellow). Pressing a square flips that light and the lights directly above, below, left and right of it. Your goal is to switch every light off. It sounds easy until a press that fixes one corner spoils another, so the puzzle is about thinking ahead. The counter shows your presses, and Par is the fewest presses that could clear the board.

Choose a board from 3 × 3 to 6 × 6. Every board is made by pressing squares on a dark grid, so each one can be solved. The Hint button highlights a square that is part of a shortest solution. Your best press count for each size is saved in this browser.

Tips

Pressing a square twice cancels out, so the order of presses never matters; only which squares you press matters, and you never need to press one more than once. A useful method is “chasing the lights”: work row by row, and for each light that is on in the row above, press the square directly beneath it. When you reach the bottom row, look at which lights are left, and use that pattern to decide which squares to press in the top row, then start again.

Is my progress saved? Only your board size and best scores, in this browser.