Prisoners' Inventions

I remember seeing a PoW exhibit at the Dayton Air Force museum, where they had all kinds of crazy things that american PoWs made in german prison camps. Including a working clock made of cardboard, and an insanely elaborate mouse trap, with many different chambers that each had a different trap.

All I could find online was this picture, which doesn't really do it justice: http://jenpowell.com/wp-content/uploads/2011/10/usaf_pow.jpg

Link to Drawings: http://temporaryservices.org/served/projects-by-name/prisone...

I think the most interesting part of prisoners' inventions is how humble they are. A salt shaker. A radio. Hot glue dispenser. Simple small things that apparently enrich a person's life enough (and makes getting through prison life better enough) to go through the trouble of building them from scratch.