An Exposure Koan

Imagine I give you a deck of cards, you shuffle it, select a card, return it to the deck, shuffle it, then you hand me the deck and I find the card. Assume I achieved this by the use of a marked deck.

You might say that’s not that interesting a trick. You’re probably right. In its most basic form, it’s not very interesting.

Okay, now let’s say I give you a deck of cards, you shuffle it, then I spread it on the table face-up and take a picture. Then you select a card, replace it, shuffle the deck and hand it to me. I spread it again on the table and take a picture of it.

“It’s a pretty complicated algorithm,” I say. “The program compares the order of the deck in the first picture to the order of the deck in the second picture, calculates in the shuffles, looks for the card that is out of sequence, and voila, it identifies the card you chose. How else?”

It’s a goof, of course. The truth is I just used a marked deck and all the picture taking and talk of algorithms was just presentation. A presentation that many would think is more interesting than just saying “pick a card and shuffle and I’ll find it.”

But, here’s where it gets complicated.

The fact is, there is an app—well, a combination of apps—that can do exactly what the “goof” presentation suggests. That is, you can have a deck shuffled, take a picture of it, have a card selected, returned to the deck, and have the deck shuffled again (multiple times), then you can take a picture and the app compares the first picture to the second and identifies which card was selected.

You need Vision: The Card Spread Analyzer by Martin Eisele

What is the point I’m making? I’m not sure, really. That’s why I called this a “koan” not “a well considered point on exposure.”

I guess what I find odd is this: if you do this trick with a marked deck, you’re a thoughtful magician putting some effort into presentation. If you do it with the app, you’re exposing the trick and breaking a cardinal rule of magic. But the experience for the spectator would be (essentially) identical regardless of which version you performed. In fact, even a knowledgable magician might have no idea which version you did if they were just watching. The president of the IBM might say, “If that trick doesn’t use an app, I’d like to write up your presentation in the Linking Ring. If that does use an app, then you’re kicked out of the IBM for exposure.”

I just find that interesting.

We’re probably due for a complete overhaul of what exposure means in an era where laymen can discover the secret to nearly any trick with a couple minutes of searching online. We can’t think of it the way we did in the 1950’s. “Call the ethics committee! Blackstone revealed the rubber pencil illusion on the back of a Sugar Rice Krinkles box!”

I don’t know what the answers are, but I have done pretty much the best writing on the subject. Specifically about how we can utilize exposure for stronger magic. See this post, Four Uses of Exposure, and the beginning of this post. That’s a starting point.