The magician shows an ace at the bottom of the pile of four cards. He then reverses the order of the deck. He shows the Ace on the top, then puts it on the bottom and it's still on top. He then visibly places three cards down and its still on top. He then puts it on the table. It once again is on top. He then puts it on the bottom and it's back on top. He then puts it onto the table. The top card is still the ace.
If that wasn't enough, he then shows every single card as a Ten of Spades, so there were no Aces what-so-ever. Then the pack turns into all kings!
