HexDome
Hexagonal Geodesic Domes
Pentagonal prism tensegrity
Here's a "floating strut" tensegrity.
Pentagonal prism

Note that the struts do not touch each other.
It is an unusual structure  since it contains no triangles.
Triangulation
Some people seem to think that structures are necessarily dependent on
the presence of triangles.
They sometimes cite Buckminster Fuller on the issue:
"Only the triangle produces structure and structure means only triangle; and visa versa"
 Synergetics, 608.05.
"By structure we mean omnitriangulated. The triangle is the only structure."
 Synergetics, 610.02.
"If we want to have a structure, we have to have triangles."
 Synergetics, 610.12.
However, no coherent explanation of why this might be so appears to have been
offered. At one point he says:
"we have learned experimentally that only triangles are stable"
 Synergetics, 401.03.
Structures like this one appear to represent experimental counterexamples to
the notion that stability depends on the presence of triangles.
The apparent stability of this totally trianglefree configuration surely casts
serious doubt on the dogma that triangles necessarily form the basis of all
stable structures.
Synergy
That this structure appears to be stable makes it a good example of structural
synergy.
It's also of interest since each strut is attached at each
end to three cables  the minimum possible for a
"floatingstrut" tensegrity.
This is the simplest model with these properties that has
been found  though it may be possible for a similar
fourstrut system to be constructed.
Pentagonal prism

Links
Pandia Raj Ramar's pentagonal model
Adrian Rossitor's hexagonal model
Bob Burkhardt's hexagonal model
TChime pentagonal model  probably a different cable configuration
Tim Tyler 
Contact 
http://hexdome.com/
