Fig. 987.210 Subdivision of Tetrahedral Unity: Symmetry #1: A. Initial tetrahedron at two-frequency stage. B. Tetrahedron is truncated: four regular corner tetra surround a central octa. The truncations are not produced by great-circle cleavages. C, D, and E show great-circle cleavages of the central octahedron. (For clarity, the four corner tetra are not shown.) Three successive great-circle cleavages of the tetrahedron are spun by the three axes connecting the midpoints of opposite pairs of the tetra’s six edges. C. First great-circle cleavage produces two Half-Octa. D. Second great-circle cleavage produces a further subdivision into four irregular tetra called “Icebergs.” E. Third great-circle cleavage produces the eight Eighth-Octahedra of the original octa. F. Eight Eighth-Octa and four corner tetras reassembled as initial tetrahedron.