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.
