Black Nightmare

A 3” cube, with a panel on each side. On two sides, this panel is split in two, both pieces moving independently. Whatever moves you do on this side, you must also do on the other side. By moving these four half-panels in unison, you can move the other sides, and eventually remove them altogether.
Not too hard to make, using 1/8" & 1/4" plywood. Minimum 13 moves.

Outside dimensions: 2.5" length, 2.5" width, 2.5" depth

Inside dimensions: 1 3/4" length, 1 1/4" width, 1 3/8" depth