Daily Binairo
The rule
Never three alike in a line, five of each per line, and no two lines the same.
Click a cell to cycle it between empty, filled and open.
Three rules, and only three. No three of the same symbol sit together in a row or column. Every row and every column holds exactly five of each. And no two rows are identical, nor any two columns.
The first rule does most of the early work: any pair of matching cells forces the opposite symbol at both ends, and a matching pair with a gap between them forces the gap.
Controls
Click a cell to cycle it: empty, then one symbol, then the other. Progress saves in this browser as you go, so you can come back to the same puzzle later today.
Solvable Without Guessing
Every puzzle here was generated and then handed to a solver that is only allowed techniques a person can use. If it could not finish the grid without a guess, the puzzle was thrown away rather than published. That also makes the answer unique, because every step it took was forced.
More to Play
There are twenty one daily sudoku variants, a 15 puzzle, peg solitaire and a nonogram with hand drawn pictures. For puzzles you can hold, see mechanical puzzles.