Dominosa (PuzzleMadness)

Dominosa starts with a rectangle of numbers and no lines. The grid is exactly a full set of dominoes laid out with their outlines removed: with numbers 0 to 6, that is the 28 pieces from 0-0 to 6-6. You draw the dominoes back in, pairing each square with one neighbour, so every pair appears once and only once.

The daily page opens today's puzzle on its own, and its title carries the date (on 3 October 2026 it read "Daily Medium Dominosa Puzzle for Saturday 3rd October 2026"). There is a separate dated puzzle for each size: Small is a 6 by 5 grid with numbers 0 to 4, Medium is 9 by 8 with 0 to 7, and Large is 11 by 10 with 0 to 9. The Mixed page is a fourth grid of its own, not a copy of one of the other sizes. On 28 October 2026 it was another 11 by 10 grid. Past days stay in the archive, so a missed puzzle can be played later, and there is a print version and an image download of the grid. PuzzleMadness does not publish solutions: the site tells you when you have finished a grid correctly or made a mistake. Each completed puzzle adds to your total on the Dominosa monthly and all-time leaderboards, where only your best score on any one puzzle counts.

Look for pairs that can only be found in one place in the grid; that domino is fixed. Corner squares with few neighbours, and pairs of equal numbers, are also good starts. Each domino placed removes its pair from every other spot, which forces more.

PuzzleMadness is a British puzzle site with dozens of daily puzzle types in the browser, from many sudoku variants to logic grids such as Nurikabe, Hashi and Slitherlink. It is free to play and carries ads. A free account keeps track of the puzzles you have finished and puts your name on the leaderboards, and the badges next to usernames mark how many puzzles a player has completed.