Abstract: A versatile modular building element, made from the agglutination of three pairs of symmetrical prisms in three overlapping tiers, provides an arched component that can be congruently meshed with a similar one in several different ways. The prism may have rectangular or obliquely parallelogrammic sides or a combination of both while keeping their triangular end walls equilateral and side walls of the same width allowing for up to eight different configurations of the building element. Elements of the same or different types can be combined to construct and infinite variety of structures exhibiting high compressive strength, stability and resistance to multi-directional stresses.