You remember the age old folk toy, the "Whimmeydiddle."  The propeller changes directions upon the will of the operator.  In this updated effect, the toy is first pulled through the side of an envelope; a routine is performed, and during this routine the spectator holds the "whimmeydiddle" and it still changes direction.  As a final ending, the toy is put back in the envelope, and the envelope is torn up - the toy has vanished.