This is very visual, and reasonably easy to do. There are no real sleights involved, but you do
need to work out the routine sequence. The one downside is that the cards aren't examinable... and
given what you're showing the spectator, they're going to have a strong urge to want to check them
out.
The only thing I don't get is, why would anyone want to buy this as a stand-alone
effect, when for a few dollars more, you can get Miracles For Mortals in which Williams covers this
effect, plus another hour+ of pretty solid material? Given this choice, I'd definitely opt for the
full DVD, and make the gimmick myself. It's simple enough to do that I wouldn't recommend paying a
premium for it.
Think about the gimmick a bit. It's pretty easy to come up with a minor variation that allows the cards to be examinable at end. You won't end clean, but easy to ditch gimmick as you toss cards on the table... Handling is a little more finicky as well; but this version FRIES! (I'll admit though, that I don't do the full IHDC routine: just a couple of shows, then drop cards on table)
-Rob