셀레브레이션 오브 사이드
Celebration Of Sides - DVD
This topological oddity is from Robert Neale's Celebration of Sides DVD.
The magician shows that two puzzle pieces fit together to form a rectangle "brick wall".
Simple enough. But when the pieces are turned around and fit together again,
there's an opening in the middle...
a portal or secret opening to the other side.
Very practical, easy, and lots of presentational possibilities.