It’s an impossible coincidence -- with an ordinary deck.
The cards are shuffled over, and over, and over again -- and each time, the spectator makes a series of free decisions. They choose everything -- which pile to shuffle into which pile, which pile to turn face up, and which pile to turn face down. They can even change their mind.

Despite all of that - despite EVERY decision - the only cards face up in the end are under YOUR complete control. The face up cards can be anything you want - their phone number, the serial number on a dollar bill, or every card in their chosen suit in order except for their selection. The possibilities are endless.