It's one thing to perform magic with a deck of cards, but it's much harder to trick an audience using only three cards.

In this display, three blank cards are shown, and with a slight circular rubbing motion, a red spot appears on one of the cards.
The magician now causes all three cards to contain a red spot.

Another rubbing motion removes the red spot from all three cards, leaving them all blank once again.

Finally, the cards are named 1, 2 & 3.
An audience member is asked to mentally choose one.

Whichever card is chosen turns out to be the only one with a red spot.
The other two a blank.

All three cards can be examined.

Here's how the trick appears.