No 2×2 Sea
Three sea cells already forming an L would complete a 2×2 block — the last cell must be land.
How it works
- 1Three corners of the top-left 2×2 square are already sea, wrapped in an L around the fourth.
- 2Water there too would make a full 2×2 block, and the rules never allow one.
- 3So the open corner has to be land.
- Island (land)
- Sea
- Cells that establish the pattern
- Where the conclusion lands