Controls

You play by pressing lights. Click a light with a mouse on a laptop, or tap it on a phone, and it toggles between on and off, along with the lights directly above, below, to the left, and to the right of it.

Two facts about how presses work are the whole key to the puzzle:

• A single press flips the light you tapped and its four immediate neighbors. Corner and edge lights simply have fewer neighbors to flip.
• Pressing twice cancels out because toggling the same light two times returns everything to how it was. That means only whether you press a light an odd or even number of times matters, not the order.

You solve the puzzle by turning every light off at once.

The grid grows larger across eight levels, so the patterns you need to find get bigger and more intricate.

Tips

• Think in patterns, not sequences. Because pressing a light twice undoes itself, the order of your presses does not matter, only which lights you press. That shifts the puzzle from a sequence to a pattern to find.
• Try the top-down method. Work row by row: press lights in a row to clear the row directly above it. Repeating this pushes all the lit lights toward the bottom, where they become easier to finish off.
• Watch what the bottom row tells you. After clearing everything above with the top-down method, the pattern left in the bottom row reveals which lights in the top row you should have started with.
• Never press a light twice by accident. Since two presses cancel out, a stray repeated tap just wastes effort and muddles your pattern, so keep track of what you have already pressed.
• Start over cleanly if you get lost. Random poking rarely recovers a tangled board. Resetting and applying a consistent method is faster than trying to fix a mess press by press.
• Notice symmetry in the starting board. Many boards begin with a symmetric pattern, and the solution often shares that symmetry, so spotting it can point you toward the right lights to press.

Frequently asked questions