psychologyTHINK GAME

LIGHTS OUT

TOGGLE ALL LIGHTS OFF

SCORE 0
MOVES —
BEST —
LIGHTS OUT
Toggle cells to turn all lights off.
Each click also flips neighbouring cells.
PERSONAL BEST: —
leaderboard RANKS
lightbulb
Expert Tips
Work row by row: A classic strategy — solve the top row, then "chase" remaining lights downward, toggling each light from the row below it.
Pressing twice cancels: Every cell is its own inverse. Pressing the same cell twice returns everything affected to its previous state.
Corners are precise: Corner cells affect only 2 neighbours, making them the most controllable moves. Save them for fine-tuning at the end.
psychology LOGICAL DEDUCTION
visibility PATTERN RECOGNITION
memory WORKING MEMORY

Lights Out

GOAL

Turn all 25 lights off. The board starts with some cells lit and you must find the right combination of toggles to extinguish every last one.

RULES

  • Tap any cell to toggle it and its orthogonal neighbours (up, down, left, right).
  • Corner cells affect 2 neighbours; edge cells affect 3; centre cells affect 4.
  • Every puzzle is solvable — there is always at least one solution.

SCORING

Base points: Easy 500 · Medium 1000 · Hard 2000. You lose 30 pts per move over par. Minimum score is 50 regardless of moves used.

Why this sharpens your mind

CONSTRAINT PROPAGATION

Deciding which cells to press requires tracking cascading effects — the same cognitive process used in logic puzzles, circuit design, and debugging code.

SPATIAL REASONING

Visualising how a toggle affects the grid and mentally simulating several moves ahead directly exercises the visuospatial sketchpad in working memory.