clockwork LEGO Useless Machine -- turns itself off

The sole function of this LEGO(TM) machine is to turn itself off. Having seen a number of electrical or electronic solutions I decided to go for a purely mechanical one. I used a LEGO clockwork motor to provide the power, which provides a lot less oomph than the electric ones. The first "working" design needed far too much torque, and the last prototype you see here works much more smoothly. I also wanted the appearance to be as close to "just a box with a switch" as possible, to have just a single hole for the clockwork key, and yet to be able to display the innards using hinges. The hardest part was probably getting the flap to operate easily and smoothly, and to open and close at the correct parts of the cycle. Careful design of the "pusher" allowed the hole to be fairly small in the later prototypes. There were probably around ten partial or complete prototypes before I found a reliable method and layout. I use the latest prototype(s) as a reference for the next, so I try to have enough bricks around to keep several on the go at once. This kind of device has been called Shannon's Ultimate Machine, the Leave Me Alone Box, and the Most Useless Machine.