Here is another approach for a tensegrity sphere. It uses suggestions in Kenneth Snelson's floating-compression patent (U.S. Patent No. 3,169,611, Figs. 21 and 22) to take the first step in creating general hex-pent spheres using X-Columns. I used Snelson's hub for the vertices, and three-stage X-Columns for the edges. The X-Modules in the X-Columns don't alternate in sense. This was necessary to get the symmetry and orientation I wanted.
This provides an avenue for the construction of very sparse tensegrity spheres and (once a truncation technology is formulated) domes. The struts are all equal length and the construction with X-Columns provides an alternative approach to double-layer domes for developing large-scale tensegrity domes that are resistent to dimpling.
Three-Stage X-Module Column Used for the Edges
(the end tendons are omitted when used in the dodecahedron)
This design was completed August 10, 2007. The dodecahedron model and the X-Module column used for the edges are available for inspection in the Dynamic Tensegrity Views.