Spectator can perform the entire change himself

He holds the matchbox with one hand and draws attention to a small hole in the center of the face of the box

Jacob Daley's The Itinerant Pasteboards:

Craft edition tuck cases made of premium Cotton Gmund paper from Germany

Then show the cup empty

Modern Flap Card (Bildseite zu roter Rückseite) | Hondo Hondo Spectator can perform the entireThe Flap Card was first introduced in 1922, in Professor R. Kunard's Book of Card Tricks . In the decades since, it has become a staple in the routines of magicians worldwide, used to produce all sorts of stunning effects. However, limitations of the original 1922 design constrain these performances: magicians must precisely position their audience, keep constant pressure on the card surface, and perform tricks almost immediately after setup for best