Every cell is Light or Shadow.
The numbers tell you how big each patch is. Nothing is hidden, nothing is random, and every board has exactly one answer — proved before it ships.
Dealing a board…
Free play deals boards like this without end — every size, and a new rule whenever you want one.
The same game as the app, free. About 25 MB to download the first time.
The one rule
A patch is a run of touching cells of the same tone. A number says how many cells are in the patch it sits on — counting itself.
Patches cannot touch
Two patches of the same tone are never side by side. If they touched they would already be one patch — which is what makes the numbers bite.
Tap, or drag
Tap to mark Shadow, tap again to clear. Long-press (or right-click) for Light. Drag to lay a whole run at once.
Gems for every board
In the full game each board pays gems — more for a bigger, harder one — and one extra for a perfect run: no undo, no reset, no cell left on the wrong tone. Hints do not count against it.
Endless boards
Free play deals a fresh board every time — small or large, easy or hard, plain or with a rule that changes how the numbers count. There is a daily board too, the same for everybody. It is all in the app, and in your browser.
Someone sent you a board?
Paste the whole link into your browser and it opens here — you do not need the app, an account, or anything else. The board travels inside the link itself.