14 / LIGHTS OUT
Lights Out
Pressing a cell flips it and its four neighbours. Switch every light off.
Lights Out board
Best -
QUICK GUIDE
How to play.
- 01
Press a cell
Pressing a cell switches it and the cells above, below, left and right of it between on and off.
- 02
Switch them all off
You win when every light is off. Pressing a cell twice undoes it, so the order of presses does not matter.
- 03
Aim for the minimum
Each board shows the fewest presses that can solve it. Match it for a perfect solve.
Frequently asked questions
Are some boards impossible?
Some Lights Out patterns are mathematically impossible. Here every board is built by random presses from an all-off board, so it can always be solved.
How is the minimum calculated?
Whether to press each cell is solved as a system of equations, and the solution with the fewest presses is chosen from all possible ones.
Any tips?
Work down from the top row: whenever a light is on, press the cell directly below it. The pattern left in the last row tells you how to change your presses on the first row.
How are scores ranked?
Fewer presses make a better score, and a shorter time breaks a tie. Scores are saved only in this browser.