Shake the smartphone to shuffle the virtual deck, every shuffle change 8 cards' positions. When the write "SHUFFLE" disappears touch two time the display to select the card.
You can force specific cards at the first and the fifth Touch (first and third Stop).
Example: set the first stop at King of Hearts and the third stop at King of Clubs. The spectator choose Ace of Spades and Ace of Clubs, You choose King of Heart and King of Clubs.
Magically you stop at King of Hearts, then you touch to restart and then the spectator with free choice, touches and stops at Ace of Spades. Then you touch to restart and then you touch again to stop at King of Clubs. At the end the spectator, with free choices, touches to restart and, with another free touch, he stops at the King of Clubs.
It's Magic.
Touch again to reset (you can also reset with a Shuffle).