(Magic Question) A big cup with a small cup. How did the coin get into the small cup inside?

Coin: The magic table is specially made and covered with a layer of black flannel. There is a gap between the upright cup and the inverted cup, just enough for a coin to pass through. There is a small opening on the desktop below the gap between the two cups, and the mechanical device under the desktop can eject coins through this opening. This small opening on the desktop is covered with black flannel, and there is also a small opening for coins to pass through.

The magician used the elastic rubber band in the sleeve to shrink the coin into the sleeve of his left hand to make it disappear, and then explained that he wanted to turn the coin into a cup, so that when the audience focused on the cup, his right hand pointed at the cup, and his left hand quietly put the coin in the sleeve into the slot behind the table. After the coins are put in, the mechanical device in the table is started, and the coins quickly bounce into the cups from the gap between the two cups, forming the effect of changing coins into cups. These are two identical coins.