Clue Full
When a clue has exactly as many free neighbours left as bulbs still to place, all of them are bulbs.
How it works
- 1This wall wants two bulbs among the four cells touching it.
- 2Two of those four have already been ruled out, leaving exactly two candidates.
- 3Two bulbs still owed and exactly two places left to put them: both are bulbs.
- 4The same counting is what makes an edge or corner clue so strong — a wall against the edge has fewer than four neighbours to begin with, so it runs out of slack sooner.
- Cells that establish the pattern
- Bulb this technique places