Patent ID: 8336274

Claim:
An irregularly-shaped building unit comprising: a front surface; a rear surface opposite of the front surface; an outer contour surface extending from the front surface to the rear surface, said outer contour surface being irregularly shaped in the planes of the front and rear surfaces; a plurality of mating sides disposed on the outer contour surface, wherein at least two mating sides intersect with a major axis, and at least two mating sides intersect with a minor axis, wherein the major axis and the minor axis are generally perpendicular to each other intersecting at substantially the center of the unit, wherein the dimension of the unit along the major axis is longer than the dimension of the unit along the minor axis, wherein each of the plurality of mating sides is a centered rotation about the respective axis that the mating side intersects with, and wherein each of the mating sides has substantially the same configuration such that each mating side of one building unit can mate with any mating side of a second building unit.