A tumbling clown walks from the left side of the frame, sticks a couple of pieces of paper on the back wall, transforms it into other clowns, and pulls more clowns from a briefcase.
It's all film magic, performed by stop motion, but it hearkens to the circus, at this time the biggest part of show business: bigger than the legitimate stage, records, and the still not quite established lively art of film. Nowadays the circus seems in terminal decline, clowns terrifying, and cinema doesn't seem too healthy -- there's a serious question as to whether movie theaters will be around at all in ten years. Not so when this was made.