The magician shows a blank, white sheet of paper and asks a spectator to sign their name on it. The spectator signs their name on the paper and then sets the sheet aside face up. A deck of cards is displayed and the spectator chooses a card. The magician places the rest of the deck on top of the signed paper and explains that the sheet of paper actually contained his invisible prediction...he lifts the deck and written on the sheet is the name of the spectators selected card! The prediction actually appears on the very same piece of paper signed by the spectator. No paper switches and the paper can be given as a souvenir. Easy to do.