Our most unexpected and fabulous cultural discovery in China was the "Face Changers" in Chengdu.  These perfomers do a stylized dance in which they change their face masks in a fraction of a second with a flick of the fan—so fast you can't see them do it.  Each perfomer will go through 15 to 20 different faces during the dance and finally end up with no mask.  My guess is that each mask is painted on silk, and that one hand is used to pull away the outermost mask by a hidden string while you're distracted by the fan in the other hand.  How it's actually done is a closely guarded secret, and the Face Changers will not take an apprentice who is not from the Chengdu area.