Binary Diagonals
Filled and hollow squares in equal measure — along both diagonals too.
Binary Diagonals is a binary puzzle with two lines more. Every row and every column holds as many zeros as ones and nowhere three alike stand in a row — and the same goes for the two long diagonals, corner to corner, which the board draws as two lines. A diagonal crosses every row and every column, so it ties the whole board together: most boards cannot be finished without reading them. A few cells are given; the rest is the puzzle. Here the board writes no digits: a zero is a hollow square and a one a filled one, a tap walks a cell from empty to filled to hollow and back, and the board tells you only what your own marks already say — three alike one after another and a mark its row, column or diagonal has too many of take a reddish wash. Nothing is ever marked as “must be the other one” — with two kinds of mark, that would be the answer.
A new board every day — 8 × 8, 10 × 10, and 12 × 12 — 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
Fill every empty cell with a hollow square or a filled one, so that each row, each column and each of the two long diagonals — the lines drawn corner to corner — holds as many of one as of the other.
Never three alike one after another — not in a row, not in a column, and not along either of those two diagonals.
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 one after another, and squares a row, column or diagonal has too many of.
Beyond today’s board
No timer. Leave and come back — it’s saved.
Play today’s Binary Diagonals