Brick Wall - Video Download (Excerpt of Celebration of Sides by Robert Neale)
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.