You are playing cards with the Devil, the prize being your soul.
The game is very simple:
- the Devil deals two cards face down;
- you both turn over the cards – if they are the same colour then you win, if they are different colours the Devil wins.
You play six times, and the Devil wins every time. He has obviously stacked the deck.
You suggest to the Devil that you should play the opposite game: if the cards are different colours you win. He agrees, and you play six times: he wins every time. Obviously He either saw this coming or He has changed the deck while you were not looking.
You suggest a third game:
- the Devil will deal two cards, face down;
- after the cards are dealt you will choose which game to play – the one where you win if they are the same, or the one where you win if they are different;
- the cards are turned over.
Much to your surprise he agrees to play once more, and you play six times. The Devil wins every time.