Lights Out
Turn off all the lights with the fewest moves.
Moves: 0
Click a cell to flip it and the four neighbors. Turn every light off to win.
About
Each click toggles the cell and its four neighbors. Goal: turn off every light. Sounds easy, isn't. The puzzle has a solvable solution for almost every starting state.
How to use
- Pick board size.
- Click cells to toggle.
- Turn them all off.
FAQ
Is every starting state solvable?+
On 5x5, 7 of every 8 starting states are solvable. The unsolvable ones can't be reached by playing from all-off, so you only see solvable boards.
Is there a known optimal solution?+
Yes. The classic 'light chasing' technique always solves it in at most twice the necessary moves. The optimal solution uses linear algebra over GF(2).