Dominosa
Cover the rectangle completely using a full set of dominoes.
Cover the rectangle completely using a full set of dominoes.
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Dominosa is a logic puzzle where you reconstruct a complete set of dominoes by pairing adjacent numbers in a grid so that each domino appears exactly once.
Dominosa is a clever and satisfying logic puzzle based on the classic domino set. The game presents you with a rectangular grid filled with numbers, typically ranging from 0 to 6 (or higher in larger variants). Your task is to reconstruct the original arrangement of a complete set of dominoes—each possible pair of numbers (e.g., 0-0, 0-1, ..., 6-6) appearing exactly once—by drawing borders around adjacent pairs of cells.
Every number in the grid belongs to exactly one domino, and dominoes can be placed either horizontally or vertically. Although the grid shows only numbers (with no pre-drawn domino outlines), the puzzle guarantees a unique solution. Solving Dominosa requires careful observation, pattern recognition, and deductive reasoning: for example, if a particular number pair can only fit in one location, or if placing a domino in a certain spot would isolate a number with no valid partner, you can eliminate possibilities and gradually reveal the full tiling.
Originally devised by O. S. Adler in 1874 and later popularized by puzzle publishers like Nikoli, Dominosa offers a quiet yet deeply engaging challenge. Its blend of simple rules and complex deduction makes it a favorite among logic puzzle enthusiasts, providing a rewarding experience as you piece together the hidden domino arrangement.
To play Dominosa, start by selecting a puzzle type and size from the "Type" menu. Click "New" to generate a new puzzle. The grid will display numbers representing the domino halves.
Tile the rectangle with dominoes (1×2 rectangles) so that every possible domino appears exactly once (that is, every possible pair of numbers, including doubles).
Use the numbers in the grid to determine where each domino can be placed. Each number represents one half of a domino.
Click between two adjacent numbers to place or remove a domino. Right-click to place a line between numbers if you think a domino definitely cannot go there. Dominoes light up red if two identical ones appear on the grid.