Polyforms, literally "many forms," are shapes that are built up from basic unit forms such as squares, triangles, hexagons, or circles.  Polyforms built of squares use the "-omino" ending.  There is only 1 domino, built of two squares, but there are 2 trominoes built of three squares, 5 tetrominoes built of four squares, 12 pentominoes built of five squares, 35 hexominoes built of six squares each, etc.


polyomino.jpg (14482 bytes)



"Polyiamonds" are built of unit equilateral triangles.  There are 4 pentiamonds built of five triangles and 12 different hexiamonds built of six triangles each.


polyiamonds.jpg (15794 bytes)



The "Polyhexes" are built of unit hexagons.  There are 3 trihexes built of three hexagons, 7 tetrahexes built of four hexagons each, 22 pentahexes built of five hexagons each, 82 hexahexes, etc.


polyhex.jpg (14049 bytes)



There are also Polytans (built of right triangles), Polyedges, Polycubes, etc.   For a more complete list of polyforms (and the numbers of each kind) see the World Game Review, issue #13 or the WGR web site or see the book Polyominoes by Solomon Golomb.  You can see all these polyform puzzles and more at gamepuzzles.com.