A small plastic frame and 5/8″ die are shown. There is a hole through the die, also through the left and right sides of the frame.
The die is inserted into the frame with holes lined up. Spectator threads a cord through the frame and die, drawing it back and forth. Spectator cannot remove die when both ends of cord are held.
However, performer removes the die while the spectator is still holding both ends of cord!
Die, frame and cord are given for inspection.
A great little close-up mystery!