Abstract: A self-supporting structural unit having a three-dimensional surface comprising: a first plurality of identical polygons, such as, for example, equilateral triangles, having predefined, fixed areas and equal sides of a predetermined constant length: and a second plurality of polygons, such as, for example, hexagons, having various areas but with equal sides of a predetermined constant length, the sides of the first plurality of polygons being equal in length to the sides of the second plurality of polygons and being secured thereto and in coextensive alignment therewith, the vertices of the first plurality of identical polygons and the second plurality of polygons lying substantially in the three-dimensional surface of the self-supporting structural unit.