Two quarters are shown and mysteriously one vanishes. This trick can also be used for penetration of solid thru solid effects. Many varied effects can be performed with shelled coins and their mates.
One coin is a shell and the other mate is a coin that the edges have been "shaved down" and remilled to fit the shell to exact tolerances.
This is not an expanded shell. This type of shell fits perfectly over it's mate. Thus, when the coins are nested, you can turnover the coin to show it as a single coin. With an expanded shell the "tolerance of the fit" is not as tight.
