Blackout
Turn every light off. Each press flips a cell and its four neighbours, so every fix breaks something else.
How to play
Press a cell and it flips, along with the cells directly above, below, left and right of it. Lit cells go dark and dark cells light up. The board is solved when nothing is lit.
That is the whole rulebook. The trouble is that neighbours overlap, so clearing one corner tends to light up another.
Par
Every board shows a par: the fewest presses that can possibly solve it. Matching par is the real game. Finishing over par still counts as solved, and the tally under the board keeps track of both.
Two things are worth knowing if you want to chase it:
- The order of presses never matters, only which cells you press.
- Pressing the same cell twice undoes itself, so an efficient solution touches each cell at most once.
Hint points at one cell from a shortest solution for the board as it stands, including whatever mess you have made of it so far.
Controls
- Mouse or touch: press a cell.
- Keyboard: arrow keys move around the board, Enter or Space presses the focused cell.