A bottle and a glass are displayed to the audience. Put them on the table and cover them with two empty tubes.
Picking up the covers, you see that the bottle and the glass have changed places. Do it again to restore the original position. Do it again and much to the audiences surprise, when you pick up the tubes, two bottles appear from beneath the tubes. Every time you pick the tubes, two more bottles appear until there are six, eight or even ten bottles on the table.