One, two.

A one, two, three, four!

♫ ♫Peg plus Cat♫ (Cat humming) ♫Peg plus Cat♫ -♫One, two, three - Yeah, come on, let's go♫ -♫Four, five, six - Hey, what do you know♫ -♫Seven, eight, nine - Whoa, what comes next♫ - Uh, ten?

- Ten!

-♫You're the best♫ ♫We are two, na na na na na♫ ♫Me plus you, na na na na na♫ -♫We're Peg plus - Cat♫ -♫Peg plus - Cat♫ -♫Peg plus - Ca-at♫ -♫Peg plus Cat♫ (laughing) - Heehee!

Dada?

- The baby problem.

- Bébé.

Hee!

Hee!

Hee!

(cheery music) - OK, so I'm Peg and this is Cat, and we're just about to finish building the best, most amazing block towers in the history of the universe FOREVER!

- They're good.

- And what's great is both towers are TOTALLY identical.

- Huh?

- That means they're the same.

They have one really big cylinder-shaped block and one, two, three, four, five, six, seven, eight, nine, ten cube-shaped blocks.

- Cool!

- Now, they just need a super cool, triangle-shaped block to top them off.

Behold their brilliance!

So tall, so smooth, so... - Yah!

- All over the floor!

- Whoops!

- Cat, you knocked down my tower!

- Sorry.

- That's OK, Cat, because, look, our towers were exactly the same.

- Except for the color.

- Yeah, so I can just copy your tower to rebuild mine.

- Phew!

Double oops!

- Oh no!

Now, both towers are knocked over, and we'll never remember how to rebuild them!

We've got a BIG PROBLEM!

(Cat crying) Cat, that's it!

We can use the diagram I drew earlier to help us rebuild our towers!

A diagram is a drawing that shows where everything goes.

And so... ♫Problem solved, the problem is solved♫ ♫We solved the problem, problem solved♫ (Ding!

Dong!)

Who is it?

- Baah!

- Oh!

Hi, Mrs. Sheep.

- Prrrrt!

- Ah!

Bwaaah!

- Hello.

- What's up?

- Maaah!

- You want us to watch Baby Fox?

Hmmm... Well, the thing is, as much as we both LOVE babies-- - Love 'em!

- Ayeee-yeee.

- Actually, they make me nervous.

- Me and Cat are pretty busy right now.

- Very busy.

- Doing really important stuff.

- Very important.

- We've got these block towers that absolutely have to be built.

- Gotta build 'em.

- Dada?

- Awww... all right, we'll babysit.

- Yeah!

- We will?

- Baaah!

- Buh-bye!

- Prfff!

Prfff!

(Cat laughs nervously.)

- Good baby.

- OK, Baby Fox, here's the deal: I'm babysitter Peg and this is assistant babysitter Cat.

- Hey, "dat".

- We're the boss of you today.

Say, goo-goo, ga-ga if you read me.

- Dada, do, day.

- Close enough.

You sit here and play nicely with these itty-bitty baby blocks while me and Cat get back to our important big-kid stuff.

- You are good at this.

- I know, right?

Now, let's get back to work.

We've got block towers to rebuild.

♫We'll use this diagram♫ ♫You know it's like a chart♫ ♫To help us recreate our tower work of art♫ ♫The cylinders are first One for you, one for me♫ ♫One end up, one end down Aha, oh yeah♫ - Whoopee!

-♫Cubes are next in line♫ ♫How many do we needy?

- Uh, um, ten?

-♫Right you are, yes indeedy♫ ♫One, two, three, four, five♫ ♫Six, seven, eight, nine, ten♫ Again!

-♫One, two, three, four♫ ♫Five, six, seven♫ ♫Eight, nine, ten♫ Yowww!

-♫The last piece is best, it's super-duper cool♫ -♫Oh yeah, uh-huh♫ -♫Our tower's gonna rule♫ - Uh-oh!

Oh no!

Yes!

-♫Our towers really rule♫ - Hey, Baby Fox, come check out our block tower masterpieces!

Baby Fox?

Baby Fox?

Come out, come out wherever you are.

- Whoa-oh-oh!

- Wah!

I wonder who built it.

- Prfff!

- Baby Fox?

(baby babbling) Uh, Baby Fox, I think you should come down now.

That looks kind of dangerous.

Baby Fox, this is babysitter Peg talking.

I repeat, you come down right now!

- Yeah, what she said.

- Eeee!

- He's not listening to us.

- No, not really.

- If Baby Fox keeps bouncing up and down and all around up there, he could fall and get hurt!

We've got a REALLY BIG PROBLEM!

- Prfff!

Prf-prf-prfff!

- Hmmm... maybe we could climb up the tower and carry him down.

The pieces are all balanced just right; one wrong step might knock the whole thing down!

Hmm... Now what?

Yes!

Great thinking, Cat!

We could blow a really big bubble for Baby Fox to jump down onto.

- Yes!

- OK. First, I'll chew it up.

-♫Chew-chew-chew chew-chew-chew-chew-chew♫ ♫Chew-chew chew-chew♫ ♫Chew-chew-chew chew-chew-chew-chew-chew♫ ♫Chew-chew chew-chew♫ - All chewed!

Here goes nothing!

- It's getting big... bigger... bigger.

(laughing) (boy whistling a tune) - It's Ramone!

Shhh!

He can't see me with gum all over my face!

(Ramone whistling a tune) He's helping my mom store old junk in the attic.

(Peg gasps.)

Stairs!

We could build stairs to climb up to Baby Fox.

We need stuff that will fit together to make these steps.

- Everything's taken.

- We'll have to search someplace else.

But we can't leave Baby Fox alone; we gotta take turns.

You go find the first piece, and I'll stay here and try to get him to settle down.

- Check!

There, we... Ah!

Ooh!

Ah!

Ooh!

Ah!

Oh!

Ah!

Oh!

Gotcha!

-♫Oh, Mister Baby♫ ♫Mister Baby Fox♫ ♫You've got a diapey♫ ♫A diapey on your bottom♫ ♫And it's so stinky♫ ♫Stinky, stinky, stinky♫ ♫Oh, Mister Baby Fox♫ ♫Goo, goo, goo, goo♫ ♫Ga-ga-ga-ga ga-ga♫ ♫Goo-goo-goo-goo ga-ga ga-ga♫ (babbling) (Peg laughing) ♫Oh, Mister Baby Fox♫ Uh... how long were you standing there?

- Long enough to hear you say diapey.

(Peg and Cat laughing) - Diapey is like underwear.

- Diapey!

(baby laughing) - Prfff!

Prfff!

- Baby Fox, be careful!

We gotta build those steps fast or he's gonna fall for sure!

Um, Cat, I'm not sure that's the right shape.

The ball is round; we need objects that are square-shaped with a nice, flat surface to stand on.

- Check!

There we... Ooh!

Ah!

Ooh!

Oh!

Ooh!

Oh!

- Perfect!

Flat and steady.

Uh, not so fast, it's my turn to search.

You need to stay here and entertain Baby Fox.

- Ha!

Ha!

Ha!

Right... (baby whimpering) No cry.

No cry!

Aaah... (baby crying) Peek-a-boo!

- Hee!

Hee!

Hee!

- Peek-a-boo!

- Aaah... Oh.

- Peek-a-boo!

(baby laughing) (Cat sighing) - One cube-shaped rock.

And this box fits just right.

OK, we're almost done!

(Ding!

Dong!)

Oh no!

Mrs. Sheep is here for Baby Fox, but he's bouncing all over and about to fall, and we'll never get him down.

We're like the worst babysitters in the existence of everything!

I AM TOTALLY FREAKING OUT!

Cat's right.

I should count backwards from five to calm down.

Five, four, three, two, one!

Our towers, that's it!

You've done it again, you amazing genius Cat!

- Moi?

- Our towers have loads of blocks; all we need to do is knock them down, and... (Peg gasps.)

We have to knock down our best, most amazing towers ever to save Baby Fox?

(Peg moans.)

Yes, it's definitely worth it.

Block knocker Cat, would you like to do the honors?

- Yeah, you don't got to ask me twice.

- Eeee!

- Hurry, he's falling!

Look.

If we put these 2 triangle-shaped blocks together, they make a cube.

- Who knew?

(baby laughing) - Prfff!

- Got ya!

- Ayee-yee... - (Peg and Cat): Awww!

So because we knew all about solid shapes and diagrams, we were able to rescue Baby Fox.

- Math really saved this baby!

Coochy-coo!

Ooh-chew-joo... (baby laughing) -♫Problem solved - The problem is solved♫ ♫We solved the problem♫ - Wow!

Totally awesome!

-♫Problem solved♫ (Ding!

Dong!)

- Baaah!

- Aaah... - Hi, Mrs. Sheep!

- Baaah!

- Was Baby Fox any trouble?

Uh... no, no trouble at all.

Right, Cat?

- Right.

- This tower's pretty high-tech.

How did you build it?

- Oh!

Hi, Ramone.

Um, well, you see, we didn't actually build this particular tower, but if we did... ♫We'd use a diagram to plan it out♫ ♫We'd use a diagram♫ ♫That's what I talk about♫ - Ayeeee!

- (together): Whoa!

-♫He used a diagram, check it out♫ ♫He used a diagram♫ - That's what I'm talking about!

-♫A rolling sphere, some dominoes♫ -♫Got a diagram - A jack-in-the-box♫ ♫And away we go♫ - Dada.

-♫Spheres, cubes, pyramids, cylinders and more♫ -♫Got a diagram - Stacked just right♫ ♫For a peaceful snore♫ (baby snoring) (clock ringing) (baby babbling) -♫Ooh-ooh-ooh ooh-ooh ooh-ooh-ooh♫ - Pee-ewww!

-♫Wipey, wipey here Powder, powder there♫ ♫Roll, toss, flip and throw him in the air♫ - Oh, yeah!

-♫He used a diagram♫ -♫To plan it out - He used a diagram♫ -♫Without a doubt - He used a diagram♫ -♫To plan it out - He used a diagram♫ -♫That's what we're talking about♫ ♫Diagram, what we're talking about♫ (laughing) - That was a pretty cool tower Baby Fox built.

- It had flashing lights, and it even changed his diapey.

(Cat laughing) - What's so funny?

- I said diapey!

- You said diapey!

- No, you said diapey!

- Diapey!

You block knocker!

- Diapey!

Closed Captioning by SETTE inc. - For more Peg and Cat, go to pbskids.org.