d object currently under the pointer.
 * PARAMETERS:
 * 	void	(MouseReturnParams *retVal,
 *		 word xPosition, word yPosition, word inputState);
 *
 * STRATEGY:		When the piece object receives this message, it means
 * 		it has been clicked on by the user and the mouse button
 * 		is still down. The piece must grab the mouse so that it
 * 		gets all future mouse events, and it must request that
 * 		all future mouse events be sent to it. This ensures
 * 		that if the pointer leaves the object's bounds while