Lights Out
Flip all the lights to off.
↑ This is Lights Out running right here in your browser — no download needed.
About the game
Lights Out is a toggling puzzle: pressing a cell flips it and its orthogonal neighbors. The goal is to turn every light off.
How to play
Click a cell to toggle it and its four adjacent cells. Plan a sequence that leaves none lit.
Tips & strategy
['Work row by row, fixing the row above with the next.', "The order of presses doesn't matter - only parity.", 'Use the fact that pressing twice cancels out.']
Advanced guide
Lights Out yields to a top-down routine. Press cells in the top row to experiment, then use each subsequent row solely to switch off the lit cells of the row above it. By the time you reach the bottom, only a few top-row patterns need checking, turning guesswork into method.
History & origins
Lights Out was released as a handheld electronic game in 1995 and became a math-puzzle favorite.
Frequently Asked Questions
Does pressing order matter?
No - only which cells you press, since pressing twice is neutral.
Is every board solvable?
Not every random pattern; generated ones are checked.
What is the best method?
Solve top-down: pressing a cell fixes the lit cells in the row above.
Why do lights spread?
Each press toggles the cell and its four neighbors.
Can I brute force it?
For small grids yes, but logic is faster.
Is there math behind it?
Yes - it is solved with linear algebra over mod 2.
Where can I play Lights Out for free?
Right on this page — Lights Out is embedded above, free, legal, and with no download or sign-up. Play with your keyboard on desktop or touch controls on mobile. Your best score is saved in your browser, so it's still there next time. Every game here is original or open-source, with links that stay valid.