A polyiamond (also polyamond or simply iamond, or sometimes triangular polyomino[1]) is a polyform whose base form is an equilateral triangle. The word polyiamond is a back-formation from diamond, because this word is often used to describe the shape of a pair of equilateral triangles placed base to base, and the initial 'di-' looks like a Greek prefix meaning 'two-' (though diamond actually derives from Greek ἀδάμας - also the basis for the word "adamant"). The name was suggested by recreational mathematics writer Thomas H. O'Beirne in New Scientist 1961 number 1, page 164.

The game uses various graphics of polyiamonds. We currently have three game types designed:
1. Tetriamond + Pentiamond
During the game, Tetriamond and Pentiamond will fall from above. You must move the graphic to the appropriate location. When combined into a complete horizontal line, the graphics will disappear.

2. Tetriamond + Pentiamond + Hexiamond
As the game progresses, two graphics will appear on the screen. You have to drag the graphic and place it on the combo board. They disappear when the shapes combine into complete horizontal or diagonal lines.

3. Hexiamond
As the game progresses, 12 Hexiamond graphics appear on the screen. You must place all Hexiamond graphics into the Diamond Combination Board. This game has 5885 combinations. Come and see how many combinations you can make.