Bad Luck by Juan Tamariz.

Juan Tamariz brings us another phenomenal effect. The spectator chooses four cards from a shuffled deck – red are good luck and black are bad. Card after card is turned over and revealed to be black, to the shared chagrin of the magician and the spectator. As the trick culminates, the magician visually changes all the black cards to red, bringing good luck to everyone. Bad Luck is an excellent example of the importance of presentation and routining. The possibilities for presentation are incredibly diverse, and the potential for intimate audience interaction makes this trick an amazing treat.