You ask the public to imagine that you are taking an invisible deck out of its case. You hand the virtual deck to a spectator who must take one, look at it (he mentally chooses a card) and put it back face up in the package.The spectator reveals their choice to the audience.You
You ask the audience to imagine that you are taking an invisible game out of its case.
You hand the virtual deck to a spectator who must take one, look at it (he mentally chooses a card) and put it back face up in the deck.
The spectator reveals his choice to the public.
You put the invisible game back in the case from which you take out a real game that you spread out in front of you.
Only one card is turned over, the chosen card.
To complete your effect, you show its back: it is blue in a red-backed game.