EFFECT:
- Five strings extend from an envelope, but only one string is attached to the winning bell at the bottom.
- Allow your spectator to choose four of the strings, and the final string remains for you.
- Pull each of the selected strings upward, and show that they are all loose strings - none of them are attached to the winning bell.
- The single string they left for you is the winner!
- Every selection is freely made by the spectator.
- Even if they decide to change strings midway, they still cannot find the winning string.