Patent ID: 7036277

Claim:
A modular building element which comprises: three pairs of symmetrical prisms, each of said prisms having two opposite and triangular end walls and three contiguous parallelogrammic side walls; each of a bottom pair of said prisms having an upper half of a side wall congruently and fixedly held against a lower half of a first side wall of one of a median pair of said prisms; each of said median pair prisms having an upper half of a second side wall congruently and fixedly held against a lower half of a first side wall of one of a top pair of said prisms; and each said top pair prisms having a second side wall congruently, peripherally and fixedly held against a second side wall of the other prism in said top pair; whereby said prisms define an arched structure having a top half congruently matable with the bottom half of a similar structure.