Three Cards Change Their Positions Seemingly By Magic

The simplicity of using only three playing cards instead of a complete deck is, I believe, quite appealing. I hope you enjoy the accompanying video, designed for viewing pleasure. It is a variation on a very old magic trick used by con-men called the "Three Card Monte", and even older as the "Shells and Pea".
Three cards are placed face down on the table.
The magician shifts them around, and a spectator is invited to choose the Ace.
No matter how closely the spectator watches, he/she is wrong. This is repeated a couple of times, and every time the spectator chooses the wrong card.