. Joseph Myers classifies the n-ominoes up to n=15 according to how symmetrically they can tile the plane.

From Scott Kim's Inversions Gallery.

K. S. Brown examines the number of polyominoes up to order 12 for various cases involving rotation or reflections. Equations linking the cases are proposed.

from the Geometry Forum. Lists the pentominoes; fold them to form a cube; play a pentomino game. (project of the month, 1995)

S. Dutch discusses polyominoes, poliamonds, and polypolygons with special attention to tiling characteristics.

About various polyforms - polyominoes, polyiamonds, polycubes, and polyhexes.

Introduction to Tetrominoes, Pentominoes, Hexominoes, Heptominoes, Octominoes, Fixed (translation only) Polyominoes. Numerous Links.

Polyform puzzle lessons for math educators to use with their students, including polyominoes, supertangrams, and polyarcs.

Secondary School project about pentominoes and fun with math. History, descriptions, and problems. Bi-monthly pentomino competition. A solver is available. [English, French, Dutch]

Amamas Software offers a pentomino solving software.