A popular version of this game is marketed as Tri-Ominos by the Pressman Toy Corp.[1] A triomino tile is in the shape of an equilateral triangle approximately 1 in (2.5 cm) on each side and approximately 1⁄4 in (6.4 mm) thick.
Each point of the triangle has a number (most often from 0 to 5, as in the Pressman version),[2] and each triomino has a unique combination of numbers, subject to the following restrictions: Given these restrictions, with the six potential values (0–5) commonly seen, there are 56 unique combinations, and thus the standard triomino set has 56 tiles.
Larger sets are possible; for example, including 6 as a possible end number would result in 84 tiles.
Tiles are most often made from plastic or resin that approximates the feel of stone or ivory, similar to most modern commercial domino sets.
Some "deluxe" sets include a raised, brass tack head in the center.
Points are scored based on the numbers on the tile played, with additional bonuses applied when special placements are made.
When a player can place a tile that completes a closed hexagonal shape (i.e. the 6th piece & all 3 numbers match), that player receives a bonus of 50 points plus the regular score for a legally placed tile, less any penalty if pieces have been drawn.
They should be aware of potential hexagons or bridges, to avoid misplacing a tile that could be valuable.
A player may consider it worthwhile to set up potential hexagons and bridges since this may or may not be to his own benefit; they may even hold the necessary tile to use in his next move.
In 2009, an app for the iPhone was launched which licensed the Tri-ominos brand from Pressman.
[6] Variants manufactured by Pressman have included "Quad-Ominos", with square-shaped tiles, and "Picture Tri-Ominos".