Binary Signs
Filled and hollow squares in equal measure — and = and × signs between them.
Binary Signs is a board of filled and hollow squares: every row and every column holds as many of one as of the other, and nowhere three alike stand side by side. Between some cells stands a sign — an = says both hold the same, an × that they differ. A few marks are given; the rest is the puzzle. Here a tap walks a cell from empty to a filled square to a hollow one and back, and the board tells you only what your own marks already say: three alike in a row, a mark its line has too many of and a sign its two cells quarrel with take a reddish wash. No hints, and nothing that checks you against the answer.
A new board every day — 6 × 6, 8 × 8, and 10 × 10 — the same for everybody, each with a single solution that reasoning alone reaches. No timer and no account needed: a board left half-done waits for you until the day turns, at midnight UTC.
Today’s boards
How to play
Put a filled or a hollow square in every empty cell so that each row and each column holds as many of one as of the other.
Never three alike side by side — not in a row, not in a column.
An = between two cells says they hold the same; an × says they do not.
Tap a cell for a filled square, tap again for a hollow one, once more to clear it. The squares the board came with stay put: tap one and they all give a shake, to show which they are.
Shown in red: three of the same kind side by side, squares a row or column has too many of, and two cells that disagree with the sign between them.
Beyond today’s board
No timer. Leave and come back — it’s saved.
Play today’s Binary Signs