How to play
Shade cells to form the stream, leaving every number on an island of exactly that many cells.
- An island is a group of unshaded cells joined edge to edge. Each holds exactly one number, and no two islands touch edge to edge.
- The stream is all one piece: every shaded cell connects to every other edge to edge. Corners do not count, for the stream or for islands.
- The stream never fills a 2 × 2 square.
Controls
- Tap a cell to cycle: blank → stream → dot → blank. A dot marks a cell you know is island; blank cells count as island when the board is checked.
- Drag to paint a run of cells at once.
- Red marks a 2 × 2 of stream, or an island that holds two numbers or has outgrown its number.
- Hint points at a cell you can deduce and says why; press it again to fill it.
- The + button makes a new board.