4 Flush by Nick Trost & L&L

A “Wild Card” effect with six cards! You show five blank-faced cards and one Four of Spades. The Four is brushed against two of the blank cards and they change to Fours! This is repeated with the other blank cards and at the finish, all six cards have changed to the Four of Spades-a Four Flush! No double-faced cards are used, yet spectators seem to see the face and back of every card!