I think this would make an intriguing gift for that coffee or tea lover.

Sorry about the poor translation below:

It is real for being astonished.

If you set this fully functional Stirling engine on a cup with cooking hot coffee (dte or water do it naturally also), give the flywheel to the left small thrust, and the genügsame apparatus begins quietly to stampfen - up to one hour long!
That is however not yet everything: Set it on a Kaltkompresse or a Kühlakku from the Gefrierschrank and throw you the flywheel for on he ram to the right also here, and even still longer.