It has been suggested to repost the below here. I hope I do not break any rules doing so:

I have found plans to a watch box in Professor Hoffmann's "Modern Magic" p.219. https://archive.org/details/modernmagic0......mode/2up

Opening the secret panel requires pressure on the top of the secret panel and on the bottom of the box to lift a catch. I understand the pressure to tilt the side panel into the box. I just cannot understand how the catch and pressure on the side panels work.

I bought a watch box and it only had the tilting panel, no catch. I'd prefer to have one made with a catch, like in the plans, so that it can be inspected by the spectator.

Any ideas?