The performer shows a large square box with four sides but no top or bottom. It is held up to the audience and they can see right through the opening. Also shown is a cylinder-shaped box (the circle) which also has neither a top or bottom, it too is shown to be empty. The circle is placed over the the square and with the right word, out pops an assistant, magically.
When the audience sees through the window after the colored cylinder has been removed, they are actually looking at the exterior or the inner cylinder and not the inside of the box. When done in this version, the illusion can be viewed in the round without having any trouble spots for the performer.
Another concept is to have the square fit over the cylinder rather that vice versa. Of course, this arrangement would make the inner hiding place a square rather than a circle. Confused yet? Wait, there's more.
Another version is to perform this effect like that of the Dollhouse Illusion. Only one cylinder and one box or square is used. The person is hidden in the cylinder, which is placed behind the square. The square is not attached on all sides, in fact the back and one side are open and ajar. When you begin you lift the square and show it to be empty, when you replace it to the stage you place it directly i n front o f the circle. The back of the square is open. When you lift the ci rcle the appearer crawls into the square from their hiding place inside of the circle. Then you place the circle into the square and over the appearer. Spin the box around and hook up the back and side. Then out pops the assistant.
If the illusion is made for table size, you can produce a rabbit or scarfs or any number of items.
Big or small, this one is a basic staple of magic.