She thought the old man had some clever trick up his sleeve.
By means of a clever trick, he made it (seem to)disappear.
Speaking unmorally， a clever trick? Oh， Socrates， Socrates， was that perhaps your secret?
A clever trick is to number the chunks to allow users to perceive how much is left and also to perceive that they are moving forward. It provides clear direction of a way forward.
He didn't have any clever tricks at all; he simply practiced drawing circles.
