[caveat emptor]

Here are three projects for anyone who likes fiddling with geometric models:

trihexaflexagon
hexahexaflexagon
truncated icosahedron:
I know of no easy way to make a model like this:


But something similar to the figure below is not very complicated or hard to make, but does take a bit of work. FR-mail me if interested and I will write up some instructions.

[dmcnash]