Patent ID: 7975452

Claim:
A cellular building block comprising: a middle beam; a first leg coupled to the middle beam such that the leg is perpendicular to the middle beam, the first leg having an inside edge with at least one protrusion and at least one recess located along the inside edge; and a second leg coupled to the middle beam such that the leg is perpendicular to the middle beam and spaced apart from the first leg, the second leg having an inside edge with at least one protrusion and at least one recess located along the inside edge; wherein the distance between the inner edges of the first and second legs is within a threshold amount of one half the length of the middle beam; and wherein the at least one protrusion located along the inside edge of the first leg is configured to fit into the at least one recess located along the inside edge of the second leg and the at least one protrusion located along the inside edge of the second leg is configured to fit into the at least one recess located along the inside edge of the first leg.