The following card trick by David Copperfield has been circulated around so many times. At a glance, it seems to be a valid magic card trick. But upon closer look, it's
just another case of optical illusion (or might even be optical deceipt!).




Now look again, take note that the cards presented are the
King of Hearts, the
Jack of Flowers, the
King of Spades, the
Queen of Diamonds, the
Queen of Flowers and the
Jack of Diamonds. You are being asked to mentally choose one card. This way your mind is conditioned to concentrate -
to focus alone - on that
one card you have mentally chosen - completely not minding about the other cards.

The next two slides are some kind of diversionary tactics to make you completely focus on your card alone and to give no attention to the other cards.


So that when the cards are shown again, your mind will
look only for that one card it has chosen
(!) and forgets altogether about the other cards ...
... so you fail to see that the original cards have all been changed by another set of cards. This time the cards shown are the following: the
Queen of Hearts, the
King of Flowers, the
Jack of Hearts, the
Queen of Spades and the
King of Diamonds! Since it is a new set of cards, whatever you mentally choose won't show up anymore! That's why when two or more people select different cards at the same time all the choices they make vanish
because the set of five cards are completely different!