Duo Unlimited
No daily limit here. Choose a size and keep going. Every puzzle has a code — share the link and a friend gets the exact same grid.
Tips & strategy
- Two in a row forces the ends: ○ ○ _ means the next cell must be a square, and so must the one before.
- A gap between twins: ○ _ ○ means the middle cell must be a square, or you'd get three in a row.
- Count the row: on a 6×6 grid, once you have three circles in a row, the remaining cells are all squares.
- Use the = and ✕ signs early — they often decide a whole pair of cells at once.
- Look for a row that is almost full: the remaining cells are usually forced by the count rule.
Frequently asked questions
What are the two symbols?
A circle and a square. They're just two states — the puzzle is the same as the classic binary puzzle (also known as Takuzu or Binairo) with extra = and ✕ clues.
Is there always one solution?
Yes. Cells are removed from a complete grid only while a solver still finds exactly one solution.
Is this the LinkedIn Tango game?
It's the same type of binary puzzle. Duo is our own independent version with daily puzzles, an unlimited mode and 6×6, 8×8 and 10×10 grids. We're not affiliated with LinkedIn.
Why is a cell red?
It's part of a rule violation: three in a row, too many of one symbol in a line, or a broken = / ✕ clue.
At midnight UTC, each game gets a new numbered puzzle (#1 was September 22, 2026). Everyone gets the same one, so you can compare times with friends. The archive lets you play any past day.