| Gyrobifastigium | |
 J26 -- the Gyrobifastigium | |
| Type | Johnson Solid |
| Panels | 4 ×  4 ×  |
| Rods | 14 × 
|
| Spheres | 8 × 
|
| Author | PolyClare 19:42, 9 January 2008 (UTC) |
This polyhedron was the 26th detailed in Johnson's seminal paper, consequently it's often notated J26, the 26th Johnson Solid. It may be formed by joining together two triangular prisms at square sides, ensuring that the axis of one prism is rotated (the "gyro" in the name) with respect to the other.
So... the "gyro" in the name is accounted for, the "bi" I assume refers to the two prisms, so what is "fastigium"? Aha!! A bit of googling reveals that fastigium = roof; peak; gable. Cool -- it's a pair of rotated roofs -- got it!
The Gyrobifastigium is notable because it is the only space-filling Johnson Solid. So I made a pair of 'em to play with fitting them together. Neat!
Other views[]
Pair of Gyrobifastigia, frolicking on a plane
Two Gyrobifastigia contemplating filling space
Related links & references[]
- Norman W. Johnson, "Convex Solids with Regular Faces", Canadian Journal of Mathematics, 18, 1966, pages 169–200.