Lights Off

How to play Lights Off

Lights Off is a pure logic puzzle played on a grid of glowing buttons. Some cells start lit in warm amber; the rest are dark. Every press flips not just the cell you touched but also its four orthogonal neighbours — above, below, left and right — so each move ripples across the board in a plus shape. Your task is to reason your way to total darkness: switch every light off in as few presses and as little time as you can. Because a press near the edge or in a corner has fewer neighbours, position matters enormously, and puzzles that look chaotic often collapse in just a handful of well-chosen presses. Three grid sizes — 3×3, 5×5 and 7×7 — take you from a friendly warm-up to a genuine brain-burner, each with its own leaderboard.

The goal

Turn every light off. The game is won the instant the whole grid goes dark. Your score rewards economy: every press and every second reduces it, so the perfect game finds the shortest solution quickly. There is no way to lose — you can keep pressing forever — but wasted presses cost points.

Where this puzzle family comes from

Toggle-the-neighbours puzzles have a proud mathematical pedigree. Mathematicians studied them in the 1980s as “sigma-plus games” on graphs, proving with linear algebra over the two-element field exactly which patterns can be switched off and which cannot. The idea reached the mainstream in the mid-1990s when a hugely popular handheld electronic version with a 5×5 grid of glowing buttons became a schoolyard sensation, spawning sequels, cousins in countless video games, and a small mountain of academic papers. The deepest classical result is delightfully strange: on the classic 5×5 grid only one in four random light patterns is solvable at all. Our generator sidesteps that trap entirely — every puzzle you receive is built by pressing buttons on a dark board, so a solution is always guaranteed to exist.

The grid and the shuffle

Choose a grid from the selector: Easy is 3×3, Medium is the classic 5×5 and Hard is 7×7. Each new puzzle is created by starting from the solved all-dark board and secretly pressing a number of random, distinct cells — a few on Easy, more than a dozen on Hard. Since pressing the same cells again would undo the scramble exactly, every puzzle is solvable by construction, and its minimum solution is never longer than the number of scrambling presses. The timer starts on your first press, so take your time reading the pattern before you touch anything.

How presses work

• Tap or click any cell. It toggles itself AND its orthogonal neighbours: on becomes off and off becomes on, in a plus shape centred on your press.
• Edges and corners toggle fewer cells: a corner press flips 3 cells, an edge press flips 4, and an interior press flips 5. Diagonal neighbours are never affected.
• Pressing the same cell twice cancels itself out completely — every press is its own undo. The order of your presses never matters, only WHICH cells you press an odd number of times.
• The counter records every press, and the bulb read-out shows how many lights remain lit, so you can see instantly whether a press helped or hurt.

Winning and scoring

The moment the last light goes dark, the win banner appears with your press count, your time and your score, and the score is submitted automatically to the leaderboard for that grid size. Your best score on this device is remembered separately for Easy, Medium and Hard. Sign in and your best results join the global rankings too.

Strategy tips

• Never press at random — every press flips up to five lights, so undirected clicking usually makes things worse. Look at the whole pattern first and plan a sequence.
• Learn light chasing, the classic method: work through the rows from the top. For each lit cell in a row, press the cell DIRECTLY BELOW it — that switches the light above off. Row by row, you sweep all the light down the board like pushing crumbs off a table.
• After chasing lights to the bottom row, only a few patterns can remain there. Fix them by pressing specific cells in the TOP row (memorise which bottom patterns map to which top presses), then chase downward once more — the board comes out dark.
• Since press order is irrelevant and double-presses cancel, think in terms of a SET of cells to press rather than a sequence. If your plan presses a cell twice, simply delete both — the shorter plan does the same job.
• For a high score, presses are precious: each one costs 5 points while a second costs only 2. A short pause to spot a two-press solution beats a fast flurry of ten.

Frequently asked questions