Light Switch is a small but tricky logic puzzle. Every tap flips the tile you touch and the tiles above, below, left and right of it, so lights you just turned off can come back on. Your goal is to make the whole board go dark. Every board is generated so it can be solved, and the game works out the minimum number of taps as the par for that board. Hit par for a perfect score, from cosy 4x4 boards to tough 6x6 ones.
How to play
- Pick Easy, Medium or Hard and press Play.
- Tap a tile to flip it and its four neighbours.
- Watch the Lit counter and try to bring it down to zero.
- Use the par number as your target for a perfect solve.
- Turn every light off to win.
Controls
- Computer
- Click tiles to flip them. Or move the cursor with the arrow keys and press Space or Enter. Z undoes, H shows a tile to press, R resets, Esc pauses.
- Phone and tablet
- Tap tiles to flip them. Use Undo, Hint and Reset below the board.
Tips
- Tapping the same tile twice cancels out, so the order of taps does not matter.
- Try clearing the board row by row: tap below each lit tile to switch it off.
- A hint highlights a tile from the shortest solution for the current board.
Questions
- Is every Light Switch board solvable?
- Yes. Boards are created by pressing tiles on a dark board, so they can always be turned off again.
- How is par calculated?
- The game solves the board with linear algebra and finds the smallest set of taps that turns all lights off.