Tri-Ominoes are a variation on standard ordinary dominoes, manufactured and marketed by Pressman Toys International Ltd.  As the name suggests, the tiles are triangular in shape with each of their three corners marked with a number (numerals not spots) from 0 to 5.  Each side of a tile measures between 3.6cm to 4cm depending on the type of set you buy.  Sets are sold in standard, deluxe, presentation, and other versions.

Tri-Ominoes come in standard sets of 56 tiles with each crystalline tri-omino made of a smooth, solid plastic called urea that gives each tile a heavy, substantial feel that players should appreciate.  The centre of each triangular tile has a brass spinner protruding slightly that facilitates the mixing and shuffling of the set and which also makes them easier to handle.

The game can be played by 2 to 6 players, by children (8+) and adults alike.  Game play is very similar to ordinary dominoes with players drawing and laying tiles with matching adjacent numbers.   Players score points for each domino they lay and there are bonuses for making hexagons and bridges and for other game situations.  The first player to score a total of 400 points, wins the game.