The spectator sees the two bills signed separately at the beginning - their signature on their bill, and yours on your bill. They fold up their bill, and you fold up yours. The two are placed into their hand. They are shocked to find that (1) the two bills are now one, and (2) both signatures are on it! This is a true magical moment, and it can be yours when you purchase this incredible video download: The Vault - Tubular.