Regular Polyhedrons were given symbols by Platon.
Regular Tetrahedron-Fire (As it resembles a fireplace) - 4 sides
Regular Hexahedron-Earth (As it is solid and steady enough to resemble the earth) - 6 sides
Regular Octahedron-Air (It is as sharp as the air) - 8 sides
Regular Dodecahedron-Space (Twelve may have been considered a good number) - 12 sides
Regular Isocahedron-Water (As it can almost roll like the water) - 20 sides