Lights Out is a logic puzzle played on a 5×5 grid of lights. When the game starts, some lights are on and some are off. Your goal is to turn all the lights off.
The twist: clicking any light toggles not only that light but also the lights directly above, below, left, and right of it (its neighbors). So pressing one button affects up to five lights at once. This makes the puzzle much trickier than it first appears.
A useful strategy is to work from the top row down. Press buttons in the second row to turn off any lights remaining in the first row. Repeat for each subsequent row. When you reach the bottom, the pattern of remaining lit buttons in the last row tells you which buttons in the top row to press — then start the process again.
Every puzzle has a solution, though some require more moves than others. Try to solve it with the fewest clicks possible. This free online version works on both desktop and mobile — just tap to toggle.