The Pillowcase of Terror | Math Magic

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10:15   |   May 17, 2019


The Pillowcase of Terror | Math Magic
The Pillowcase of Terror | Math Magic thumb The Pillowcase of Terror | Math Magic thumb The Pillowcase of Terror | Math Magic thumb


  • Wazzzzzuuuppp ding dongers?
  • It’s me Ding Sauce.
  • Today we’re going to enjoy a little bit of MMM, Michael’s Math Magic.
  • Thirteen years ago I discovered this pillowcase in a graveyard in Cincinnati and I could have
  • sworn it was smiling at me.
  • It was so weird.
  • I was like “Wipe that grin off your face pillowcase.” and it was like “No, how
  • about that?
  • I’m not going to do what you say because I am the Pillowcase of Terror.”
  • And I was like “okay that sounds pretty bad.
  • I’m gonna leave.”
  • and it was like “No no no sorry it’s just the name my parents gave me.
  • I’m actually pretty nice.
  • Really all I do is take that which is out of balance and I make it equal.”
  • And I was like okay yeah sure but if you say it that way it still sounds scary.
  • Anyway long story short we became friends but it is after all the Pillowcase of Terror
  • so I have to keep it locked up.
  • But if we’re quiet enough we should be able to let it out.
  • Hannah could you make sure the door is locked.
  • Yeah.
  • Okay everyone hold your breath.
  • Don’t let it know you’re living until I have it in my hands.
  • Okay.
  • We’re good?
  • Okay.
  • The Pillowcase of Terror.
  • Let me show you one of the things that it does.
  • It freaked me out when I learned it so here’s a deck of card.
  • Nice bid ol’ cards.
  • Boom.
  • Nice and big.
  • I’m gonna put these in the Pillowcase of Terror and I’m gonna meditate on my greatest
  • fear.
  • That which I wouldn’t wish upon even my worst enemies.
  • Look at that.
  • Now the first time this happened to me I was like “That is amazing” and the pillowcase
  • was like “These small cards were always inside me you just put the big ones in and
  • then you let go of them and you picked up the small ones.”
  • I was like “Ahh you’re right.”
  • Okay so that wasn’t magic.
  • But today we’re gonna do some real magic and this will defy reason so to protect us
  • I’m gonna be using my Greek philosopher playing cards.
  • You could really use any deck you want but this one makes me feel safe.
  • Now the power of the Pillowcase of Terror is a little bit frightening to me honestly.
  • But I think we might be able to outsmart it today.
  • Let’s see.
  • Hannah what’s your favorite number?
  • 6.
  • 6, okay.
  • 1, 2, 3, 4, 5, 6.
  • And uhh Jack what’s your favorite number?
  • 5.
  • 5?
  • Okay.
  • 1, 2, 3, 4, 5.
  • 6+5 is 11 so we have an odd number of cards here.
  • That’s good.
  • I like that.
  • Here’s how we’re gonna test the pillowcase.
  • I’m gonna take the 11 cards and turn them face up so now we have 11 face-up cards.
  • Easy, great, perfect.
  • Now I’m gonna shuffle these face-up cards into the rest of the cards which are face-down.
  • Perfect.
  • Okay.
  • Push them together.
  • Let’s give them a few little moves like this.
  • I’ll do a little riffle and then a little cascadey-dude.
  • Beautiful.
  • Great.
  • Okay so we now have a shuffled deck of a card, 11 of which are face-up.
  • And there those face-up cards are sort of randomly distributed throughout the deck.
  • What I’m gonna do now is take this deck of cards and I’m going to put it in my hands
  • inside the pillowcase of terror.
  • It won’t be pretty but when I am done, and the pillowcase is done and I take my hands
  • out I will be holding out two piles of cards.
  • They may not have the same number in them, I don’t know but what I do know is that
  • the number of face-up cards in both piles will be equal.
  • Ready?
  • Ohhh!
  • Okay they’re getting really hot!
  • Okay!
  • It’s done!
  • It’s happened.
  • I now have two piles of cards.
  • They’re not of equal size but they should have the same number of face-up cards each.
  • Let’s see if the case has done its work.
  • Okay.
  • In this pile we have 1, 2, 3, 4, 5, 6, 7 face-up cards.
  • In this pile we have 1, 2, 3, 4, 5, 6, 7 face-up cards.
  • 7 face-up cards in both piles.
  • That’s why they call it the Pillowcase of Terror.
  • Okay so how does this trick work?
  • Well believe it or not this is just a regular old pillowcase.
  • There’s nothing special about it.
  • Fooled you right?
  • You don’t need to be scared of it and it has no magical powers.
  • This trick is self-working.
  • It’s math magic.
  • As long as you follow the right procedure you will always get the result that you want.
  • All you have to do is count out some number of cards.
  • Let’s say seventeen.
  • 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17.
  • Now I’m gonna flip these cards over and they’re now face-up.
  • When I shuffle them into the deck it really does not matter where they go.
  • You could even have a friend do this.
  • You could have some member of your audience do this.
  • We really just wanna mix them all around.
  • And there’s no trick involved into where they go.
  • We just wanna have those 17 face-up cards in the deck somewhere.
  • Doesn’t matter where they are.
  • Then you take seventeen cards out of the deck.
  • Doesn’t matter from where but it’s easiest to take them right off the top.
  • 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17.
  • Now what I do is I take the 17 I took off the top and I flip them over and boom both
  • piles now have the exact same number of face-up cards every time.
  • For real let’s take a look.
  • This pile has 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and this pile will also have 12.
  • Watch.
  • 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12.
  • How does this work?
  • It’s actually quite simple.
  • When I take some cards out of the deck.
  • Let’s say 24 in this case.
  • Here’s 24 cards.
  • I take out 24 cards and I turn them over.
  • I now have 24 face-up cards.
  • I shuffle them into the deck.
  • There are 24 face-up cards in the deck.
  • Could be any number of cards though.
  • There we go.
  • 24 cards are now face-up in this deck.
  • I then remove that number of cards from the deck from the top for example.
  • 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.
  • Perfect.
  • Now what do we know.
  • We know that there are a total of 24 face-up cards all together.
  • We also know there are 24 cards here.
  • So how many face-up cards are here?
  • We’ll call this Pile A. And we’ll call this one pile B. In pile A, how many cards
  • are face up?
  • I don’t know!
  • I shuffled them.
  • It’s all kind of random.
  • I didn’t pay attention to where I put them.
  • Let’s just call that number X. Okay.
  • So in this piles of 24 cards, x of them are face-up.
  • So how many are face-down?
  • Just 24-X.
  • Now how many cards in this pile are face-up?
  • Well, we know that there’s 24 face-up cards total.
  • And x of them are in here.
  • So the number of face-up cards in this pile, Pile B, is 24 minus the x that are in here
  • so we have 24-x face-up cards here and we have 24-x face-down cards here.
  • When I turn one of the piles over.
  • Doesn’t actually matter which one every face-up card becomes the opposite, face-down.
  • And every face-down card becomes faced-up so we have the same number of face-down cards
  • in A as we did face-up cards in B. I just changed all of those face-down cards to face-up
  • cards so now we have the same number of face-up cards in both piles.
  • Interestingly you can choose to reverse either half so long as you don’t reverse both of
  • them and that is the trick of the Pillowcase of Terror.
  • Also known as cards in the dark.
  • Missmag himself didn’t even give it a name.
  • He just did it and it’s amazing.
  • But I love the trick and it’s really fun to use these sort of concepts and mathematical
  • principles to develop your own magic.
  • So have fun, keep your pillowcases locked up, and as always, thanks for watching.

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More about the trick: https://www.riddleministry.com/riddles/cards-in-the-dark/1333/

Mismag822's tutorial and demonstration: /watch?v=VaNCbEduGm0

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Michael Stevens
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Hosted by
Michael Stevens

Edited by
Hannah Canetti

VFX by
Jack Merline

Music from AudioNetwork


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Vsauce3: http://youtube.com/vsauce3