invisible thread stuck to the yellow ball, and passing through a hole in the top above the cup! Then he makes a movement with his hand, to pull the string! Then the ball is above the cup, and when he comes back with his hand, the ball goes into the cup! Note that he hardly moves the ball inside the box, because it has an invisible string attached to it! Simple
I might be wrong but I think the partition is a bad idea. It has a few problems. it takes away some of the mystery and possibly even telegraphs the method.
@@pavlovsunhappydog ~ Yes, also notice how carefully he adjusted the placement of the box at 0:04 so as to be over the air flow. The partition served to guide the air flow. At 1:03, he seems to signal to cut off the air. It's a very good trick, though.