Abstract: A construction apparatus for models, stagecraft, models of matrices and the like. Elements with locations at equal increments construct a mosaic of locations and points in a tetrahedron solid or portion thereof with each selected point in predetermined angular and linear relationship to every other selected point in the mosaic. A selected ratio in size constructs a scale model of a full-size structure with corresponding mosaics. Components rotate at any location. Adjustable elements select any point in relation to said mosaic. Any component is movable to any corresponding location in said mosaic. An integral connector may include two parts facing outwardly on opposite sides of a location. First part includes a resilient snap-ring in a retaining groove adjacent to a polygonal recess. The first part engages a second part with a polygonal protrusion at a location in a second element. The edges of said protrusion expand said snap-ring to engage the two parts in a predetermined orientation.