A bulb lights its row and column until a black square stops it. No other bulb can stand in that light, so every square it lights gets a dot. It’s the most used technique in Light Up.
This is one of the Light Up techniques. Each page shows its technique on the same 12×12 from the game, Hard level 4.
The rule
- Take a bulb.
- Follow its row and column outwards in all four directions, stopping at the first black square or the edge.
- Put a dot on every square you pass.
In a real puzzle
On the 12×12 every technique page follows, it’s first needed at step 6. The bulb placed in row 3, column 7 at step 5 lights 12 squares along its row and column, and none of them can have a bulb.
How often you’ll need it
On every one of the game’s 150 levels, more than any other technique: 6.9 times per Easy level on average, 12.6 on Medium and 16.5 on Hard. It’s 16 of the 42 steps on the 12×12 here.