Lights Off

How to play Lights Off

Tap any square. It flips between on and off, and so do its up to four direct neighbours. Diagonal squares are not affected. Turn off every light to finish the level. Each level shows a target move count. Match it or beat it for three stars.

Levels are created by pressing random squares on a dark board, so every level is guaranteed to have a solution.

Useful facts

• Order does not matter. Pressing A then B gives the same board as B then A.
• Pressing twice undoes itself. No square ever needs pressing more than once in an optimal solution.

The chase-the-lights method

1. Go row by row from the top. For every light that is on, press the square directly below it. This clears that row.
2. When you reach the bottom, only the last row has lights on. The pattern there tells you which squares in the top row to press.
3. Press those top-row squares, then chase the lights down again. The board will clear.

About this game

Lights-out puzzles were sold as handheld electronic games in the 1990s and are often used to teach linear algebra. This version is Homivoo's own, with levels that grow from three to fourteen presses.