stirlingEngine.jpg
This attractive cup-perched craft project is actually a working papercraft model of a Stirling engine being sold by a Germany science novelty catalog. Sitting on your tea or coffee cup, the heat (or cold) from within will power the engine for up to an hour. The kit costs EUR21.90 (around US$30).

The Stirling engine kit – [via] Link
Human translation of the catalog copy – Link