I based this project on a "classic" room, 4 walls, a ceiling and a floor. The room is accessed from below by piston. Once in the room you can start the walls rotating! Though you can see the way out through the glass, you have to rotate the room until the sand wall is above the floor pistons and open them to get out. Not a very useful device, but fun imho!

Any feedback, especially ideas for uses for this, are welcome!