Three-dimensional truss based on the rigidity of the triangle and composed of linear elements subject only to compression or tension. Its simplest spatial unit is a tetrahedron having four joints and six members. A space frame forms a very strong, thick, flexible structural fabric that can be used horizontally or bent to a variety of shapes. The beauty of its open latticework web of lightweight tubular diagonals is only surpassed by its structural purity. R. Buckminster Fuller used this technology for some of his Dymaxion projects; in his Union Tank Car warehouse, Baton Rouge, La. (1958), a space frame reinforces an enormous geodesic dome.