Balance a freely selected card upright on the table, and with nothing
else, cause it to fall over on your command.
Well you could have just blew it right? Wrong. To prove your newly-acquired
powers are real (not just air), you place their card against the card
box, and cause it to again fall down under your influence.
They've seen the magic. Now they can Feel it! The spectator signs their
selection and a corner is torn from it. Under James Randi-esque conditions,
you can cause the corner to fly off their hand, finally proving that psychokinetic
phenomenon is REAL.