Twofold
Binary puzzles with same and different signs. Circles and diamonds, half and half. Never three alike in a row, and signs tell you same or different. Rules, techniques and new puzzles every day in four levels.
Rules
- Fill every cell with a circle or a diamond.
- Every row and every column holds as many circles as diamonds.
- Never three identical symbols directly side by side or one above the other.
- “=” between two cells: same symbol. “×”: different symbols.
- Cells with a grey background are given.
- Tap to switch between circle, diamond and empty.
- Right-click or long-press to switch backwards.
- Keyboard: arrow keys move, 1 or A sets a circle, 2 or B a diamond, 0 or Delete clears the cell, space switches.
Techniques
Every hint in the game names one of these techniques and shows where it applies.
Sign
An “=” between two cells means the same symbol, a “×” means different symbols. Once one side is filled, the other side follows.
No three
Three identical symbols may never follow each other directly. Two alike in a row get the other symbol at both ends, and so does a single gap between two alike. Two empty cells joined by an “=” next to a circle must be diamonds, and vice versa.
Full
Every row and every column is half circles, half diamonds. Once a line has enough of one symbol, all its other cells get the other one.
Balance
Count what a row or column still needs. Two empty cells joined by a “×” bring exactly one circle and one diamond, two joined by an “=” bring two matching symbols. Often that leaves only one option for the other cells.
Squeeze
When a row or column needs only one more circle, every other empty cell gets a diamond. Put the circle in the wrong place and three diamonds end up side by side somewhere. Such places get a diamond. The same works the other way round for a missing diamond.
Either-or
Every cell has only two options. Try one: if it leads to a visible contradiction within at most two forced moves, the other one holds. No puzzle asks you to think further ahead.