Think a Card (iOS Magic) by Richard Zeng (video+PDF).

Turn your iPhone into real magic — no apps required Effect A spectator names any card. You never touch your phone. They pick it up, unlock the screen… Their card is already on your lock screen wallpaper. Fully examinable. No explanation. Features No apps Built entirely using native iOS functions Ultra clean and completely hands-off Always ready, anytime, anywhere Includes 3 prediction styles: Oil painting Playing card reveal Building light display Important Notes Works only on your own iPhone iPhone only (not compatible with Android devices) English performance required (not suitable for other languages) Includes only Online tutorial