[bright music] - Hi there, friends at home.

My name is Lily, and I'm so happy to be here with you today.

You know, I've been looking out my window out a lot, because it's still kind of cold here in New York City.

And I'm just so excited for the spring.

And as I was looking out my window, I realized that my window is a rectangle.

I know that because it has four straight sides.

It has four right corners, and the opposite sides are the same length.

Look around where you are.

Is there a rectangle nearby?

Hmm?

Well, that got me thinking about rectangles even more.

I looked to the side of me, and realized this wall is a rectangle.

That wall is a rectangle.

The wall in front of me is a rectangle, and the wall behind me is a rectangle.

And then I looked up.

The ceiling is a rectangle.

I looked down, the floor is a rectangle.

And all of these rectangles fit together.

They make a box.

I'm living in a box.

I wonder if Omar lives in a box, too.

Let's give him a call, and see.

Omar, Omar, Omar.

- Lily!

Hey!

It's good to see you.

- Hi, Omar, how are you, friend?

- I'm doing good, what's going on?

- Well, I was just thinking about how I live in a box, Omar.

All of the walls around me are rectangles.

The ceiling is a rectangle.

And the floor is a rectangle.

Do you live in a box, Omar?

- Well, let me see.

Yeah, the ceiling's a rectangle.

And the walls around me, rectangles.

And the floor, yeah, Lilly, I live in a box, too.

I'm in a box!

Huh?

This makes me think, Lily.

You and I have played a lot of games together, at home with rectangles, and other shapes.

But those have been flat shapes, like this.

- Yeah.

- But the box that we're inside of, made up of all these rectangles, that's something different.

That's a 3-D shape.

- 3-D?

Three Ds?

D, D, D?

- Yeah, sort of.

The D stands for dimension.

3-D objects have three dimensions, which means they aren't flat.

They fill up space.

Like this.

- Oh.

- See how it takes up space.

- Yes, I see.

Huh?

- Let me show you another 3-D object.

One that I think might help us understand.

So, this is a very famous 3-D object, that I actually, that I recently visited myself, here in Egypt.

Can you guess what it might be?

- Hmm, are there really famous boxes in Egypt?

- Well, it's not a box, it's another type of 3-D object.

It's a pyramid.

Do you know about the pyramids in Egypt?

- Omar, I have heard of these very famous 3-D shapes.

- Okay, let me tell you more about them.

So, they're enormous.

Look how small I am next to the Great Pyramid.

- Oh, my.

- I know.

Well, when I first walked up to it, when I first saw that pyramid, I saw a big triangle.

But then I started walking around it.

And I saw another triangle.

And then I walked a little more, another triangle.

And then I walked a little more, another triangle.

And I realized that pyramid that huge pyramid, is a 3-D object.

It's made up of many flat shapes.

All the triangles together, are on the sides.

And the square, at the bottom, they make the pyramid.

- So cool, Omar.

I really want to be visiting a pyramid.

- Well, Lily, you can.

And friends at home, you can, too.

Pretend you're here with me in Egypt.

Let's all pretend that we're inside a of pyramid.

Here, I'll show you how, stand up, stand up.

Okay, so we're going to imagine we're inside a pyramid.

So we have to draw the triangle walls around us.

Draw the first wall.

One.

Two.

Three.

Four.

And Lily, don't forget the square floor underneath you.

Okay, now we're inside of our pyramid.

Let's dance.

And friends at home, be careful not to hit your head on the sloping walls.

[lively dance music] - Omar, that was so fun.

I loved dancing in my pyramid.

And as I was dancing, Omar, I was thinking, there's a very famous building nearby, where I live in New York City, that I think is one of these special 3-D shapes that you're talking about.

Let me show you, and I wonder if you can guess what it is.

- Lily!

That's the Flat Iron building in New York.

- It is!

- I love that building.

I used to walk by it all the time.

Okay, so this is a 3-D object.

So I see that it has flat shapes on every face of the building.

I see the long rectangle on one side.

And a long rectangle on the other side.

And, I can guess, I'm pretty sure that there's another long rectangle on the back.

And then, there's a triangle on the top and the bottom.

Lily, the Flat Iron Building, it's a different type of 3-D object.

It's a triangular prism.

- Oh, triangular prism?

- Yeah, so far we explored a few types of 3-D objects.

We've explored pyramids, and triangular prisms.

- Oh, and weren't we also talking about boxes?

- Oh, yes, yes.

- Is that a special 3-D object?

- Yeah, great job, Lily.

A box is a rectangular prism.

- Oh.

- You know, Lily, there are big 3-D objects all around us.

Like the pyramids, like the Flat Iron Building.

But there also smaller 3-D objects, right in our very homes.

- Wait, there's 3-D objects all around me?

- Yes, Lily, just like the box that you're in, they're all around you.

And I have a game that will help us find them.

It's called "3-D Shape Scavenger Hunt".

[triumphant music] [excited children shouting] This game, Lily, helps us find the shapes, that make up 3-D objects.

So, here's how we'll play.

I'll show you a shape face, and then both of us will go searching to see if we can find a 3-D object that has that shape, as one of it's faces.

Friends at home, you can play, too.

We'll all look for objects that have the same shape face.

It's a fun, 3-D shape scavenger hunt.

- Oh, sounds great, Omar.

I'm ready to play.

- Okay, our first shape is a circle.

[bell ringing] When I say go, find a 3-D shape that has a circle face.

Ready, set, go!

[lively music] Okay, Lily, what did you find?

What 3-D object did you find that has a circle shape?

- All right, I found this canister, which has a circle on the top, and a circle on the bottom.

I found this candle.

It also has a circle on the top.

And a circle on the bottom.

And then, I realized, my yoga mat, when it's rolled up, there's a circle on this side, and a circle on this side.

What about you?

- Whoa, Lily, you found so many, Lily, great job.

I found in the kitchen, this can.

Which has a circle on the top.

And a circle on the bottom.

You know, Lily, these 3-D objects that we found, the ones that have circles, they have a special name, too.

These are cylinders.

- Ah, cylinders, cool, Omar.

Okay, I'm ready to find a new shape.

- Okay, here we go.

Find a 3-D shape somewhere around you, that has a triangle face.

[bell ringing] Ready, set, go.

[lively music] Lily's still searching, let's see what she finds.

Lily, tell me, tell me.

What 3-D object did you find with a triangle face?

- That was kind of hard, Omar.

But I realized this candle holder has a triangle on the bottom, and a triangle on the top.

But rectangles on the sides.

And then, I found this thing that my candle was in.

There's a triangle on every side.

Omar, I think this is like that pyramid that you were telling me about.

- Yeah, Lily, you found two different types of 3-D objects.

You found a pyramid, and a triangular prism.

Really good job.

You know, I have to say.

I didn't, I wasn't able to find any 3-D objects with a triangle face.

It's kind of hard.

But if I find one, I'll show you later.

Okay, okay, let's search for our final 3-D shape.

Lily, friends at home, find a 3-D shape that has a rectangle face.

[bell ringing] Ready, set, go.

[lively music] - What did you find?

- Okay, Omar, you know, this book is definitely a rectangle.

And when I move it, and look at the sides, there's rectangles on every side.

And then I found these two boxes.

One is quite long, and one's a little shorter.

They have many rectangle sides.

And they have two sides that have a special type of rectangle, a square.

What did you find, Omar?

- Okay, I found this box of face masks.

Which has a rectangle on every side.

I also found this piece of chocolate.

Which has a rectangle on every face.

- Oh, I love it, Omar, this is so fun, searching for these shapes.

But you know what, Omar?

I just feel like I wanna dance.

- Let's dance, then.

And I have an idea.

When we're dancing, why don't we each pick a type of 3-D shape that we'll dance inside.

Friends at home, you do the same.

Ready, let's dance.

[lively dance disco music] - Omar, it always feels great to dance with you.

- Ah, it really does.

Lily, I noticed you were dancing in a lot of circle patterns, spinning and spinning.

Were you dancing inside of a cylinder?

- You know I was.

What about you?

What were you dancing in?

- I was dancing in a rectangular prism.

I was trapped in a box.

Lily, thanks so much for playing with me today.

And friends at home, keep a look out for 3-D objects, big and small, all around you.

Pay attention to the faces on the 3-D objects.

What face do you see?

And if you want, you can turn it into a fun scavenger hunt game, like we did.

- Thanks so much, Omar.

That was so fun, I learned so much about 3-D shapes.

And thank you for playing with us, friends at home.

Remember, math is all around you.

Go see what math you can find today.

- Bye, bye, Omar.

- Bye, Lilly.

Bye, everyone.