💡 Lights Out

spatial · Wildcard, weekly

Pressing a cell flips it and its four neighbours. Turn every light off, in as few presses as you can.

Every press flips the cell you touched and the four around it, so progress in one corner undoes progress in another. Turn the whole grid off. It is the oldest kind of puzzle on this list and still the one that most rewards noticing that order does not matter, only which cells you pressed an odd number of times.

When you will see it

Lights Out is a Wildcard. It takes the fourth slot for a week at a time, on a rotation through twelve candidates.

The rules, in one line

This is the same sentence the app shows above the board, so nothing here is a paraphrase of the real rule.