Lego recreation of the "Most Useless Machine"

YouTube user Invisibules recreated Minsky and Shannon's "Most Useless Machine" (a box with a switch on it; switch it on and a hand emerges from the box and flips the switch to off) using Lego: '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.'

The Most Useless Machine Ever Made in LEGO (video) (Thanks, stagueve!)