Lights Out is a logic puzzle on a 5×5 grid: every tap flips a light and its neighbours, and your goal is to turn them all off in as few moves as you can.
Tap any light to toggle it together with the lights directly above, below, left and right of it. The puzzle is solved when the whole grid is dark. Every puzzle is guaranteed solvable.
Pressing the same light twice cancels out, so the order of moves doesn't matter. Only which lights you press matters, so you can plan a solution on paper.
Lights Out first appeared as a handheld electronic toy in 1995 and has been a favourite of puzzle fans and mathematicians ever since.
Yes. Lights Out is completely free and runs directly in your browser. There is nothing to download or install and no account is required.
Yes. Pixel Arcade is built to work on desktop, tablet and mobile browsers, and the controls adapt to touch screens as well as keyboards.
Yes. After your first visit, Pixel Arcade caches its single-player games so they keep working without a connection.
Your best scores, coins and achievements are stored on your device, and you can optionally back them up by signing in from the main arcade page.