Dug North directs our attention toward this interesting collection of mechanical paper-mades –

This new Paper Locksmith Collection from Flying-Pig Paper Animation Kits includes a twelve page booklet about locks and locksmithing. You also get three working paper lock models to download, print, and build: a Combination Lock, a Cylinder Lock, and a Warded Lock.

On top of the obvious papercraft fun – looks like an enjoyable way to understanding lock-work in general – Paper Locksmith Collection