How to play
- Goal
- Separate each pair of numbered beacons into its own pale island while keeping one connected river.
- How it ends
- A chart completes when every cell is marked, every island has exactly two numbers with area strictly between them, and the river has no 2×2 pool; there is no loss.
- Record
- Your first solve time is kept per chart, and the fastest verified first solve appears with its holder.
- Separate the numbered beacons into pale islands. Each island must contain exactly two numbers, and its area must be strictly greater than the smaller number and strictly less than the larger. The remaining river cells must make one connected stream, and no 2×2 square may be all river. In the worked sketch, a two-cell island is allowed between 1 and 3; adding a third cell makes it invalid.
- Tap or click a cell to cycle empty, river, land. Drag paints the chosen mark across cells; a cancelled gesture restores its starting state. Right click cycles backward. Numbered beacons stay on land.
- Undo reverses one stroke. Restart clears marks but keeps the original clock. A chart completes once every cell is decided and every island, river and 2×2 rule holds; there is no loss.
Controls
| Tap / click a cell | Cycle empty → river → land → empty |
|---|---|
| Drag | Paint the chosen mark across cells |
| Right click | Cycle backward |
| River / Land / Erase | Mark the selected cell directly |
| Arrow keys | Move focus through the chart |
| Space / Enter / X | Mark river / land / empty at the focused cell |
| Z | Undo one stroke |
| R | Restart without resetting the clock |
| Escape | Close a panel or return to the atlas |
All 160 fixed charts have one independently verified answer, are distinct under square symmetries, and require strict area bounds for uniqueness. Private solver and answers do not ship. Progress and reduced motion use morass.nuraf.v1; sound uses the shared site setting. No ads or analytics run inside the game.
About Nuraf
In a moonlit grotto, numbered brass beacons rise from pale stone islands while a single blue river winds between them.
Explore 160 fixed charts from 5×5 to 7×7. Every chart has one independently proved answer, and its strict area bounds matter to that answer.
The clock begins when you open a chart. Your first solve stays on this device; an uninterrupted first session can set the verified public best time shown with its holder.
