Here is a view down a 3-fold
axis. It is 12 cm in diameter.
And here is a view down a 5-fold axis.
Here are the ten modules. Each has three
H parts. Four of
the modules
are in a triangular configuration and six are in a zig-zag
configuration.
There is a unique solution, and it has a nice tetrahedral symmetry.
I later made a version of this puzzle in nylon by rapid prototyping
(Selective Laser Sintering).
This material is more flexible, so a better choice for this design.
Here, the ten pieces from the previous image are now assembled.
It is 7 cm in diameter but I should have made it a little larger.