iPhone & iPad · In development
DuoForm
Filled or hollow. Every circle counts.
Balance filled and hollow circles, follow the clues, and work through a grid at your own pace.
App Store release in preparation.

How it works
- Every row and column needs equal filled and hollow circles.
- No three matching circles together, across or down.
- Follow the = and × clues. Completed rows and columns must be unique.
Choose a board size and difficulty, or try the daily challenge. Hints explain a cell before you decide to fill it.
Free to play with ads. An optional one-time purchase removes ads and includes unlimited hints.