JAMES GRIME: OK, so, the superflip--
so let me write down the superflip for you.
Rubik's cube fans have a notation, and they call this
the up, they call this the down, they call this the
right-hand side--
for obvious reasons-- the left-hand side, the front,
which is facing me--
and the back, which is facing away from me there.
So it's got up, down, left, right, front, and back.
I can write down the superflip using this idea.
It's going to take 20 moves.
I'm going to write down what the 20 moves are, then we'll
try it out.
Looks like this--
up.
So I'm going to turn the up once.
Now, this means right-hand side twice--
once, twice.
Front--
that's towards me--
once.
Back-- that's over here.
That's the back--
right.
Right-hand side again.
Back twice.
Look at it there.
Oh, one, two that one too.
Right.
Up twice--
one, two.
Left--
back twice--
one, two.
Right--
"U" dash-- that means the opposite direction--
anticlockwise.
Down--
anticlockwise.
Right-hand side twice.
Front.
Right-hand side backwards.
Left.
Bottom twice--
once, twice.
Up twice--
once, twice.
And then do the front twice, so once, twice.
Look at that.
So there are 20 moves there, and this was
superflip, the cube.
From the solved state, you get this really pretty combination
there, and this is the furthest away from being
solved that you can get.
Now, if you look at it, what's happened is all the corners
are perfectly fine.
You see, this is the orange face.
All the orange corners and the center are just fine.
This is the orange face.
Look at the edge pieces.
This is the orange-white edge, and it's flipped over.
Turn it 'round.
This is the orange-blue edge, and it's flipped over.
This is the orange-yellow edge, which is flipped over.
And that's the orange-green edge, and that's flipped over.
So all the edge pieces flip over.
All the corners are absolutely fine, and the centers are
always fine.
They don't move at all.
There's a couple of cool things about this superflip
that I haven't told you yet.
So if I do the superflip twice--
so the superflip was 20 moves.
If I do it twice, I will get back to where I started.
In mathematics, we say it has order 2.
You do it twice, and you'll get back to where you started.
So that's pretty cool.
The other cool thing about the superflip is that if I do a
bunch of moves, and then I do the superflip, you'll get the
same answer as if you do the superflip first, and then you
do that bunch of moves.
So you'll get the same answer.
So if you do superflip first, and stuff, or if you do stuff
first, and superflip, you'll get the exact same position.
In fact, superflip is the only move that isn't just doing
nothing at all.
It's the only move that has that property.
MALE SPEAKER: Because I would have thought that would be
true for everything, but it's not.
JAMES GRIME: It's not true for everything.
Now, that's really important.
So if I do a move followed by another
move, the order matters.
The order matters.
You get a different answer if you do it in a different
order, if you swap those over, except for the superflip.
Only the superflip--
this works.
The order doesn't matter.
MALE SPEAKER: Oh, whoa--
lock up.
No!
Wha--
oh, man.