Hoberman Sphere

The famous expanding and contracting ball toy that also makes excellent structural support for whatever sparse scaffolding you need. Basically, if you can design it as a geometric solid, you can probably make a collapsible version with this. In a pinch, also doubles as a jack or a reacher-grabber claw.

I was looking to build a NautilusX model http://en.wikipedia.org/wiki/Nautilus-X and realized that Thingiverse didn't even have a Hoberman sphere library. It uses one-way snaps might be useful for other projects too.

I'm not nearly clever enough to invent the Hoberman sphere. Thanks to Charles Hoberman for the original concept and helpfully detailed drawings.