Effect-
magician shows children frame with three holes in it black on one end silver the opposite.
the watch as the magician ties a silk thru the left hole black end.
he puts it quickly behind his back and it moves to the right silver end
the children soon notice that the magician is just turning it over and the colors are opposite the other side
then he admits defeat but does it on more time.
but this time the silk jumps to the centre hole!
