Abstract: Light weight tension-compression equilibrium structures include structural units which contain a plurality of compression members in contact with each other in an interior portion of the unit and a plurality of tension members in contact with them and exerting balanced tensions on them to hold them in position with respect to each other, and to produce compressive forces in the compression members which are directed toward the point(s) of contact of the compression members in the interior of the unit, thereby strengthening the compression members and the structural units. The tension members are positioned apart such distances along the compression members less than lengths at which the compression members alone would buckle under applied compressive forces. The various structural units may be essentially planar, useful for forming walls or relatively thin supporting structures, or they may be made three-dimensional so as to be capable of serving as major load-bearing units.

Abstract: A construction set is comprised of a plurality of hollow 26 faceted joint elements with the facets being arranged in a selected orientation and having an opening, located in each facet, which is configured for receiving an elongate strut for interconnecting a plurality of the joint elements to form a three-dimensional framework. The struts have clip fasteners at each end adapted for snap fitting engagement within the openings such that they are not separable merely by application of tensile force to the struts; and locking means are provided for preventing inadvertent disengagement of the struts from the joints.Due to the particular geometrical configuration of the joint elements, the openings and the clip fasteners both are elongate in order to provide maximum clip strength without sacrificing the structural integrity of the joint elements.