In the mid 90s I played around with incorporating electronics into magic. Anverdi had a great idea where a box would close just before a spectator selected card could be placed inside it. I didn't like the mechanics of his box, which was a box for two decks where one half was used for the electronics and the other half for the actual action. The sliding lid of the box would slowly close. Here is a video for the original Anverdi box:
After I read Anverdi's book I could build the variation...
As a boy I made many slingshots ever since my father showed me how. Find a y-branching twig, cut it to size, attach rubber bands, and a piece of leather to hold your projectile. I must have made dozens of them. I loved the compactness of a slingshot. I also liked to make bows and arrows but those were not weapons you could put in your pocket. And they were harder to make for a boy. Finding straight arrows was one of the problems. With a slingshot any pebble, cone, or other smallish piece of something...
Go figure this one out. Three boxes, big, medium, small, stacked inside each other. So far so good. But hey, what is this? The small box is now large enough to hold the medium and big boxes?
This is my rendition of Lubor Fiedler's ingenious Gozinta Boxes (also known as Parabox or Inside-Out box). (The reason I am touching the boxes so gingerly is that they are 20 years old made from now brittle cardboard. Nevertheless, this effect is one of my favorite illusions.)
For those who know...