It is not really a control but helps you control a card. I have an older Hoyle magic book that has
almost this exact method so I am skeptical of the "underground status". Some claims in the text are
a bit misleading, I can't elaborate without giving away the method. Should have been a MUCH cheaper
download.
That being said it is useful for few times with a deck but caution doing it many
times with the same deck, meaning I wouldn't want to do this is for multiple groups or participants
in one night.
I was thinking 3 stars for the review but the price made me choose 2 stars.
The method is okay but you probably already know something similar.