August 16, 2002

1:12 PM

Wow your friends[google] and learn a little history behind the best card trick. [pdf]
posted by psychotic_venom (17 comments total)

Well, I guess you can't wow anyone that reads Mefi.
posted by psychotic_venom at 1:14 PM on August 16, 2002

card tricks suck.
posted by andrewzipp at 1:17 PM on August 16, 2002

I had a hunch those "lovely assistants" were smarter than they looked. Apparently they're math freaks...
posted by zekinskia at 1:23 PM on August 16, 2002

My brother does magic - he has this great card trick where he makes four piles of four cards with an ace in each pile. Then he puts one of the piles under the foot of his hapless victim. He then proceeds to make the other three aces disappear from the other three piles, and they all end up under the victim's foot. I've seen it 4 or 5 times now and it still amazes me.
posted by starvingartist at 1:27 PM on August 16, 2002

Well, there's an easy (and obvious) way to double the "signal" -- have the assistant pass any particular card face up or face down. But of course the point of this trick isn't the magic itself, it's the math.
posted by dhartung at 1:59 PM on August 16, 2002

The "best" card trick wouldn't require a confederate.

I remember doing an amazing automatic card trick when I was a kid -- it worked every time, seemed like magic, and required no skill other than counting (as I recall).

Unfortunately I guess the details got lost after one too many bong hits a couple years later, and I can only remember the part about basking in the warm glow of the oohs and ahhs.
posted by crunchland at 2:16 PM on August 16, 2002

The Birkhoff­von Neumann theorem states that the convex hull of the permu-tation matrices is precisely the set of doubly stochastic matrices: matrices withentries in [0, 1] with each row and column summing to 1. We will use the equiva-lent discrete statement that any matrix of nonnegative integers with constant rowand column sums can be written as a sum of permutation matrices.6To prove thisby induction (on the constant sum) one need only show that any such matrix isentrywise greater than some permutation matrix.

Oh Jesus, my head just caved in.
posted by bradth27 at 2:32 PM on August 16, 2002

Anyone remember that trick where the final step is to slip a stack of four cards between the knuckles of the participant's closed fist, smack the stack of cards with your hand, and "The Card" is left behind, stuck between the participant's knuckles?

I was really good at that one.

This trick is pretty cool, but difficult. Requires memorization and quick recall by the assistant as well as the magician. But it is very clever indeed. Tricks that require assistants lose a bit of their lustre though, cause you can't just whip out a deck of cards by yourself and show off. Oh well, an interesting read.
posted by Succa at 2:41 PM on August 16, 2002

"Do you like card tricks?"

"No, I hate card tricks," I answered.

"Well, I'll just show you this one."

He showed me three.

-- Somerset Maugham, "Mr. Know-All"
posted by DevilsAdvocate at 3:05 PM on August 16, 2002

My favorite card trick involves four completely non related words:
Atlas, Bible, Thigh, GooseAnyone else know this one?
posted by Scottk at 4:00 PM on August 16, 2002

I remember doing an amazing automatic card trick when I was a kid -- it worked every time, seemed like magic, and required no skill other than counting (as I recall) ... unfortunately I guess the details got lost after one too many bong hit

Shot in the dark. If you have a deck of cards handy, play along at home.

Step One: Take a deck and randomly discard ten cards. (I prefer to do this before the trick starts and never tell the audience, but you can do it in the middle if you're feeling honest.) Now deal the cards into piles like so. Flip the top card from the deck face up, announce the value aloud ("seven!") and place it on the table as a foundation to a pile. Now continue to deal cards onto that pile, counting upwards with each card, until you hit thirteen. So after putting the Seven face up, you would deal five cards onto it, counting "Eight", "Nine," "Ten," "Jack," "Queen," "King!"). If the foundation card is an Ace you will create a 13-card pile; if it is a King it will constitute a pile unto itself. When a pile is complete, start a new pile with the next card. If the last cards in the deck do not make a complete pile (e.g., you flip over a "Three" but only have seven cards remaining, set the remainders aside for the moment.

Step Two: Flip all the piles face down. Ask your audience to pick three of them. Take all the unchosen piles and combine them with the cards you set aside in step one (*not* the ten you took out before you started -- those never re-enter the trick). Hand the deck to your audience.

Step Three: Tell your audience to flip over the card on top of one of the three face-down piles. After he has done so, tell him to discard that many cards. So if he flipped over a Nine, he would discard nine cards from his deck. Now have him flip over the top card on a second pile and repeat the process. If you did *not* remove ten cards prior to starting, now tell him to discard ten "for good measure".

Step Four: Ask your audience to count how many cards he has left in his deck. Then tell him to flip over the top card on the last of the three face-down piles. If you've done everything correctly, the value of the card will equal the number of cards he still holds.

Sounds numbingly mathematic when described, I admit, but it's pretty neat in practice and hard to screw up.
posted by Shadowkeeper at 4:25 PM on August 16, 2002

Shadowkeeper - just tried it, then did it with the kids. Amazing trick. I'll have to keep that one in the back of my head to pull out and impress folks.
posted by jazon at 5:42 PM on August 16, 2002

That sounds close, but not quite.

There were piles of cards, all right, but the more I think about it, it involved telling a story while counting out the cards -- a story about the 4 jacks, travelling around the world or something. Each jack started out in different piles, and then all ending up in the same pile, and that was the trick. Or something.
posted by crunchland at 7:15 PM on August 16, 2002

Shadowkeeper: step three left me with zero cards!? Am I doing something wrong? How much does a face card count for in step three?
posted by kozad at 7:29 AM on August 17, 2002

dammit, i just gave this trick to the kids at mathcamp a week ago -- more specifically i told them to figure out how to do this trick and then demonstrate it in a timed contest. I think about 3 teams managed to do it.

There's another trick I want to try that is not guaranteed to work but is something that occurs with about 90% probability. I'll have to find a description of it somewhere.
posted by meep at 8:42 AM on August 17, 2002

Am I doing something wrong?

Must be. At all times Jacks = 11, Queens = 12, Kings =13.
posted by Shadowkeeper at 10:44 AM on August 17, 2002

One question, Psycho:

Why the numeric link on the Google search? Any idea? I'll assume you didn't do that on purpose...
posted by baylink at 12:40 PM on August 17, 2002