Question 1

Is every board solvable?

Accepted Answer

Yes. Every puzzle starts with all lights off and is scrambled with real presses, so pressing the same lights again always solves it.

Question 2

How do you know the fewest possible moves?

Accepted Answer

Lights Out is a system of on/off equations, one per light. Solving it exactly (Gaussian elimination over GF(2)) gives the shortest solution for every board.

Question 3

Where are my bests and streak saved?

Accepted Answer

In your browser's localStorage: your fewest moves for each grid size and your daily streak. They never leave your device.

Question 4

Can I play with a keyboard?

Accepted Answer

Yes. Use the arrow keys to move around the board and Enter or Space to press a light. U undoes a move.