Patent ID: 6053661
Filing Date: 2000-04-25
Classification: E02B,E03F

Abstract:
A plurality of specially-shaped solid blocks for use underground as aggregate, the blocks having elongated protuberances and mating recesses on each face, the protuberances and mating recesses on a face all mutually parallel and also parallel to an edge of the face, the protuberances and mating recesses on each face oriented in one of a plurality of possible orientations, each solid block having at least two different orientations of protuberances and mating recesses in that if any one of the blocks is rotated about an axis through its center and parallel to an edge of a face so as to rotate into view different faces, the protuberances and mating recesses continue in one direction, and if the same block is then rotated about another axis perpendicular to the first axis and so as to again rotate into view different faces, the protuberances and mating recesses alternate in alignment by ninety degrees, thereby providing that the plurality of blocks fit closely together only when arranged in a small fraction of the number of ways the blocks can be arranged, and providing a pre-determined void in a volume when distributed throughout the volume with some minor disorder.