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John introduces a large box with a slit at the top. Inside, he places his wallet full of cash, his expensive watch, and even takes the daring risk of adding his wedding ring (and, humorously, his wife!). The box is then padlocked by a spectator, who tests a series of keys on the lock but finds that none of them open it.
John then reveals that he holds the key capable of unlocking the padlock. The spectator mixes this key with the others and, one by one, taps each key against the side of a wine glass, John carefully listening to the sound it produces. Keys deemed "duds" are dropped through the slit in the box, rendering them inaccessible.
Amazingly, against all odds, John identifies the correct key solely by the sound it makes and uses it to unlock the padlock, completing the incredible demonstration!
