| Finally, the octahedron inscribed in the Venus-orbit sphere has itself an inscribed sphere, on which the orbit of Mercury lies. |
| While writing, I may choose a clear Quartz Crystal for clarity or a yellow Fluorite octahedron to help keep creative thoughts flowing. |
| Theaetetus was the first to study the octahedron and the icosahedron and it is believed that Book XIII of Euclid's Elements is based on his work. |
| These give the solid angles of the tetrahedron, the octahedron and the icosahedron. |
| This six-point perspective, with the six vertices of an octahedron serving as the vanishing points, becomes the basis of his spherical paintings. |
| The large four-sided facets above and below and to the right and left of the table are the faces of the octahedron. |
