Long-press a tile to preview its 3×3
Long-press a tile to preview its 3×3
Join every blue tile into one sea.
Turn a scatter of sand and sea into one connected sea.
The tile you tap and all 8 around it swap: sand ↔ sea. On edges and corners, fewer tiles flip.
Long-press a tile (or hover with a mouse) to see exactly which 3×3 it will flip. Let go to cancel.
You win when every blue tile touches another blue tile by a side and they all join into a single body of water. Any shape counts.