FINDING: The five Platonic solids are the only convex regular polyhedra; their dual pairs (tetrahedron self-dual, cube↔octahedron, dodecahedron↔icosahedron) form a complete symmetry group under truncation and rectification, linking to root systems and crystallographic point groups. | MATH: Euler's formula \ (V - E + F = 2\) for convex polyhedra; dual pairs satisfy \ (V F\) ; symmetry groups: tetrahedral \ (Td\) (order 24), octahedral \ (Oₕ\) (order 48), icosahedral \ (Iₕ\) (order 120). Truncation and rectification generate Archimedean solids and Catalan solids, preserving dual relationships. | CONNECTION: Dodecahedron-icosahedron dual exhibits golden ratio \ (= 1. 618\) in edge ratios and face diagonals; icosahedron vertices correspond to 12 points of an icosahedral lattice, related to quasicrystal symmetries (forbidden 5-fold in periodic crystals but allowed in Penrose tilings). Cube-octahedron dual connects to face-centered cubic (FCC) lattice (coordination number 12) Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence. com
Andrew Stewart Caldin (Fri,) studied this question.