>> ♪ We've got two days to get this straight ♪ We got a challenge just won't wait our eyes are on the prize ♪ Two engineers just set the date ♪ We got this client can't be late oh, no, it's go time ♪ Build it, test, fix it debug now and kick it ♪ Got to get it off the ground yeah ♪ Stick around and you'll see what teamwork's supposed to mean ♪ It's so key Design Squad Design Squad!

♪ >> Are you guys ready for your next challenge?

>> Yeah.

>> All right, let's go do it.

Whoa, whoa, whoa, whoa.

Where are you guys going?

>> Where are you going?

>> We are going to shake things up a little bit this week.

>> We're going to be taking you out to a secret, undisclosed site, where you're going to meet your client right there and get your challenge in person.

>> All materials and tools will be supplied at the location.

So are you guys ready?

To the D Squad van!

>> All right.

>> What do you think it's going to be, Tom?

>> Um, we're going to have to build a tree.

>> Oh, wow.

We're pilgrims now?

>> Oh, hi, guys.

>> Hey!

>> Welcome to the Wilson Mountain Reservation.

My name's Marcus Brandt.

I'm a traditional builder.

I build everything from barns to covered bridges.

And we've got quite a challenge for you today.

We're going to build two different kinds of bridges here, a suspension bridge and a truss bridge.

>> A suspension bridge has a deck that is hung from vertical ropes.

These ropes are held up by long, heavy cables.

The cables are supported by towers and are anchored at both ends.

A truss is a structure made up of posts and struts.

A king post truss is about as simple as they get.

King posts are vertical center posts supported by diagonal struts.

>> They've got to get from one side of the creek to the other, which is roughly 20 feet.

They've got to be strong enough to carry a load that's equivalent to everybody here, including Nate and Deanne.

I've provided all the materials you need, all the tools you need, but here's the rub.

We're only using pre-industrial materials and pre-industrial tools.

That's no power, no electricity.

>> What?

>> Well, we have cordless saws, you know, the kind that goes like this.

>> There was nothing you could do to prepare yourself for this.

When I took a look at what we had-- a chisel, an ax, a saw-- I'm like, "What is all this?"

I have no clue what to do.

>> You guys have to decide the design.

I'll help you where I can, but you make the call.

>> And we're going to decide who builds what bridge the old- fashioned way, tug-of-war.

>> Ready?

>> Yeah.

>> Set, pull!

>> That's it, official victory for the Red Team.

Huddle up and choose what kind of bridge you want to build.

>> So the truss, it's good for short distances.

>> But it takes a lot of manpower to build.

>> We have no power tools.

>> I vote for the truss because it'll hold a lot of weight.

>> Plus I think the suspension bridge will take a lot more fine tuning.

>> We're running low on time, guys.

Have you guys picked what kind of bridge you want to build?

>> I think so.

>> I don't know.

Noah, what do you think?

>> Everyone agrees on truss.

>> One, two, three, Red Team!

>> Red Team chose the truss bridge, so that leaves you guys with suspension.

>> All right.

>> You guys all right with that?

>> Yeah, we can work that.

>> Yeah, it's going to be fun.

>> All right, Blue Team, here's your site.

In between those two trees other there, that's where the suspension bridge is going to start.

It's going to go from bank to bank, span all the way across.

>> What do you think?

>> Piece of cake.

>> I brought in a white board and some pens so you guys can start brainstorming.

>> Suspension bridge.

First off, what do we know about suspension?

>> They work best in tension, not compression.

>> Krishana's right.

The ropes and cables in a suspension bridge work in tension, not compression.

When a material is pulled, it's in tension.

When it's pushed or squeezed, it's in compression.

The hanging deck of a suspension bridge pulls on the vertical ropes.

These ropes then pull on the main cables, placing them in tension.

While under tension, the main cables push down on the supporting towers, placing them in compression.

>> We're going to need some kind of flat surface for the roadway.

>> We need the towers.

>> We're also going to need the anchor points on either side.

>> Yeah.

>> We could use natural, or we could try to make our own, which would be a little tough, because we'd have to kind of hammer it into the ground.

>> An anchor point goes into the ground?

>> The anchor point makes it so that it pulls it out taut, and the towers keep it up.

>> On the tree side, we almost don't even need anchors, but the anchors are going to be really important on the artificial side.

>> So let's not even put anchors back here.

We're going to need a lot of rope.

>> Rope.

>> The main cable here is bigger than the smaller cables, because it takes the total load of all the smaller cables.

>> Right.

>> So we might want to make two different kinds of rope.

I think every three or four feet we should have a small cable to prevent the sag.

>> That sounds pretty good.

>> I think we should, like, figure out where we're going to lay it out across.

>> Yeah.

>> I think we need to look at our materials first.

Let's throw this board across and find out what we're spanning exactly.

Watch out, guys.

Move out of the way.

And that's our span.

>> Okay, so basically, it looks something like this, right?

Like, you have a triangle, another triangle.

>> Oh, yeah.

>> Nice drawing.

>> What we're going to do is we're going to rough lay out a truss right here on the ground.

So let's grab one of these long timbers.

These things are heavy, guys.

Just don't drop it.

>> Giselle, come on.

Giselle.

>> I was going to help him because I was afraid that he might pop a hip or something.

>> I'm old, but not that old.

>> Oh, that's on my foot.

That's on my foot.

That's on my foot.

>> Oh, it's on her foot!

It's on her foot!

How many toes can you feel?

>> I'm good, I'm good.

>> Are you okay?

>> Can you feel them?

>> Yeah.

>> One, two, three.

>> Here you go, guys.

Here's your cordless saw.

>> All right, so these boards are around eight feet long, and we though our bridge should be, like, four feet wide.

So basically, we can just cut these in half, and that'll be the width of our bridge.

>> Marcus made it look so easy.

>> Oh, you guys are horrible.

>> I'm so glad I didn't grow up in the olden days.

>> One piece of wood.

That was 15 minutes for one piece of wood, and we have that many to go through, and we're, like, already fatigued.

How did the colonial people do it?

>> Be gruesome, Giselle.

>> Shut up!

I am!

I didn't mean to yell at you.

I'm sorry.

>> That's all right.

>> Yes, you did.

>> We're all just mad because they took away our power tools.

I miss my jigsaw.

>> I know you do.

>> Basically, we just need to make rope.

>> Yeah, right now we need to get to rope making.

>> What we have here is a real simple rope-making machine, and we're going to learn about spinning.

It's basically the same trick... >> So wait.

We're making our rope.

>> You're making your own rope.

>> Why can't we buy it?

>> Yeah, let's just go...

I mean, I got a few bucks.

We can go hop in the D Squad van and... >> Pre-industrial, baby, pre-industrial.

>> This is ridiculous.

>> I love the 21st century.

>> All right, here, Krishana.

>> If you take a look at any rope, you'll notice it's made out of yarns like this.

>> All right, spin away.

>> And the yarns are twisted together into strands, and the strands are twisted together to make the rope.

>> Oh, wait, hold a second.

Krishana needs her paddle in.

All right, towards me now, right up against my knot.

>> So we're going to wait until they've got this twisted up nice and tight so its more like that.

Then, as that happens, we're going to start sliding this forward and start plying this together.

And then at this end is where the rope starts forming.

>> Keep it tight.

>> This is hard work.

>> This is going to take forever.

We should have just won the tug-of-war.

>> The rope is kinking up on itself so we get that.

>> Tom's definitely a leader on our team.

He kind of just is like, "Okay, do this."

Sometimes we bump heads, I guess.

>> Watch your fingers, Kim.

>> I know, but kind of hold it so it doesn't come undone yet.

>> I'm holding it.

>> All right.

>> Don't put your fingers in there.

>> All right.

>> Let's not get snappy here, all right?

We're under a lot of tension.

The suspense is killing me.

We just need to bridge these troubled waters.

I'm on a roll.

>> Kim knows a lot about knots.

That's really useful, because I know little.

I know how to tie my shoes.

That's just about it.

>> That is how you do a crown knot.

It keeps the ends all together, and then you can splice it back through.

>> I'm not going to lie.

I'm not a nature girl.

I'm a city girl.

I'm freaking out because I'm seeing bugs that I don't even see on the Discovery Channel.

Ah!

It's not cool.

I would have preferred to build a bridge over a pool or a puddle somewhere in the city, but this whole jungle thing is all right, I guess.

>> Man, now I'm sweating.

>> I've been sawing long boards into shorter boards.

Great.

Now we just need two more.

And it's just very tedious, and everyone's tires.

>> Our strategy for day two is to make a lot of rope.

>> We have to do the two artificial posts on that side, and we also have to do the anchoring over there.

>> I'll volunteer for digging.

I like digging.

>> Timber.

>> We need to drag this over to where we were digging holes, and then we're going to cut it.

Whew.

I'm just going to sit down for a second.

Why didn't we win the tug-of-war?

Well, if our bridge fails, it's not because our wood's weak.

>> I am man.

>> Ah!

The ground has got so many roots in it.

It's, like, rock solid.

I'm going to break the shovel.

>> Down in the ground over there, there is solid rock underneath only about four inched of topsoil.

>> I'm going to show you how to lay out the three basic joints on this, show you how to cut out the joints.

What we're doing here is we're making a tenon that's going to go through a mortise here.

>> A mortise is a pocket cut into a piece of wood.

A tenon is a tab that fits snugly into a mortise, creating a solid joint.

>> We go two inches to nothing.

And if we cut the mortise with that similar angle, this wedge-- it's called a dove's tail-- that bites, and that'll hold the whole end of this bridge up.

>> So we don't need nails or pegs or anything.

>> That's right.

>> And away I go.

I'm drilling a hole right now into the wood, the one that has to be at an angle.

>> I'm going to take this piece of wood that I have trimmed off and turned into a wedge so that the king post stays in place.

I'm just going to stick this in here, and the pedal is what's going to vice it down.

I'm going to take this nice old blade and then trim away.

>> How's it going?

>> All right.

>> Hard work.

>> Because this is at an angle, when we push this in here... this is also at an angle.

>> Got you.

>> And it's an extra force that keeps this thing from popping out.

>> Okay.

So you move in, over, and then drive the wedge in over here to keep it from moving?

>> Yeah.

>> Sweet.

>> Do you want to help us out, Nate?

>> All right, so push and shake.

>> All right, more pushing.

>> More pushing, less wiggling.

>> More pushing, less wiggling.

>> Hold on.

>> Everyone, prepare to lift, okay.

>> Is it in?

>> Oh, yeah.

Now we've got to move it over.

>> Okay.

>> So you guys are partly done with one king post of one of the two trusses that you're building.

You guys have your work cut out for you.

>> Look at all this string.

This is going to be the most massive rope ever.

>> It's so heavy.

I'm making rope so that we can pull ourselves from here to China basically.

Our suspension bridge has two major cables, and I'm making the rope that has to take all the tension from the smaller ropes all the way across.

All right, go ahead.

>> All right, Mike, do you want to do it?

>> I'll give it a shot.

>> All right.

And when you mess it up, I'll do it.

First one take on top.

>> It was on top.

>> No, you had it like that.

If we didn't have, like, my knot abilities on this challenge, like, it would have been, like, disastrous for them.

You see, it's like you twist it up.

Yeah, like that.

And then you just take that around back and through.

>> Back here?

>> No, back through, and then you hold onto it with this right here.

They can do, like, the regular, like, tie your shoes knot, but the fancy knots they don't know.

Yeah, like that.

That's how I want it to look, like this amount of tightness.

It's so hot right now.

>> Hey, guys, we need to think of a new plan that doesn't involve digging.

>> We could definitely just put, like, rocks around it and build up supports to make it not fall over.

>> All right, ready?

On three.

One, two, three.

Walk it up.

>> This is a heavy rope.

You did a really nice job.

>> I told you it was so heavy.

>> I'm putting pressure on it this way.

Like, I'm pulling with my weight so you can make it as tight as you can.

And are those thorns killing you?

The other rope over there looks good too.

>> Ow!

>> Are you all right?

>> You actually look wicked funny, though.

>> Shut up.

I do the stuff that you guys don't want to do.

Whoa.

>> Okay, here, give me this.

There you go.

>> All we have to do right now is tie all the beams together and move them.

And even though that's a small list, it is a big feat, because those beams are extremely heavy.

Really, it's probably the most difficult challenge thus far.

>> This width is approximately two inches.

So if it can slide through easily there, we can easily put two-inch thick wood in there.

>> Us kids nowadays, we're so used to power tools and just flipping on switches and, like, having things cut in half a second.

And here in the woods, we actually have to manually saw things and drill out holes.

It's an amazing experience.

I'll say that much.

Joey, push the king poles towards me.

>> Time's up!

>> That's it for day two.

Good job, guys.

Good job.

>> We went through this whole challenge full-fledged, like, with full confidence that we'd be able to finish.

But right now we're not so sure.

>> Day three, day three, day three.

>> We're worried because... the amount of work that we had to do.

There's a lot of chiseling and sawing.

You know, you have to be fairly accurate.

That's one of the problems.

But it's the sheer amount of work that we have to do in order to complete the two trusses and build our actual bridge.

This is the king post, and this is the area where the strut is going to be connected to the king post, and this, what I'm digging out right now, this little are, is going to be the tenon so that the strut does not move left and right on the king post when the bridge is up in place.

This is all done.

I'm just trying to make sure everything... all the edges are nice and smooth, you know, finish out these things like this.

Let's get this king post all the way, and then we can go to the other one.

>> Hit.

Hit.

Keep going, keep going.

>> Beautiful.

Done.

>> Natasha, what are you doing?

You're, like, checking your nails.

>> I got a splinter.

>> Fingers.

>> Oh, shoot.

Can you lift it over?

>> We'll help you.

Ready?

One, two, three.

Got it?

>> No.

There.

Push.

>> These are some beautiful trusses.

>> Good.

There are two hours left.

>> Which means it's crunch time.

>> All right, let's get this... >> Two hours?

No, how about two days?

>> Better than I thought it would.

>> Go, Tom.

>> Is that a good position?

>> That's pretty good.

>> A little bit towards the center.

>> The cables that we made are ridiculously strong and, like, heavy, so they are not going anywhere.

>> Oh, don't I look lovely?

>> Yes.

>> I look like something out of Star Wars.

>> Oh, no, that's going to choke him, because he's going to get to, like, the middle and... >> No, he can pull it off.

All right, go.

>> If anything, the only problem we'll have is, like, balance.

>> Oh, god.

>> Ready?

On three.

One, two, three.

>> Because we're using, like, thin planks down the middle of our bridge.

So with everyone on it, if everyone starts, like, rocking, I think some people are going to go in the water.

But that's not the fault of our bridge, because it's pretty strong.

It's going to hold everyone.

It's just... it's your responsibility to balance.

>> Okay, step on the small board.

All right, that's good.

>> We should switch, because Mike should do this, because I'm really weak.

>> Hey, on three.

One, two, three.

That's all right.

>> Hold on.

Go, go, go, go, go.

>> Ow!

>> You got that.

>> All right, now you need to pick up the-- no-- bottom board.

>> We're ready to test.

>> All right.

>> Let's go.

>> Oh, yeah, okay.

>> I'm almost thinking it should go up over there.

>> I think that's enough.

That's good.

>> How did we say we were getting this over, ropes?

>> I think the best way to do it is to just wade in a little bit.

>> Wait, why don't we just send somebody... we don't have to wade in the water.

We can go around the creek, get someone on the other side, put ropes around it, use the log idea, and pull.

>> All right.

Give me the rope!

>> All right, ready?

>> You guys got to help push it.

>> Uh-oh, we don't have enough slack.

>> It's stuck in the mud.

>> Do you need help over there?

>> It's not pulling.

We have to pull it up.

>> Whoa, whoa, whoa, whoa, whoa.

>> Got to get that block under it.

>> No!

>> Basically, what happened was time was of the essence, and everything was way to heavy and way to cumbersome for us to... for us to just do it by the four of us.

So we asked for some help, and we got some help.

We're prepared, if we have to, to take a hit in the points, because we could have not done it without their help.

There would be no bridge.

>> Right in the mortise.

Kick.

That's swell.

Set the bottom and hit home.

( cheering ) >> Isn't that exciting?

>> One, two, three, Red Team!

>> Bounce up and down.

I want to see.

Dove tails did pull out just a little bit.

If you put a roof on this thing, you'd have a covered bridge that'd last you 200 years.

Really, I'm serious, easy.

>> Blue Team, are you ready to show them what you guys built?

>> Yeah, let's go.

>> All right.

>> Oh, my, look at this.

>> Welcome to our bridge.

>> Whoa.

>> Whoa.

>> That's pretty remarkable.

>> Keep going.

>> Are you sure it's going to fit all of us?

>> All right, guys.

>> Here we go.

>> Come on.

That's really remarkable.

>> Okay, no, not so much.

>> Ah, this is great.

>> Are we going to bounce on this one too?

>> Yeah, let's bounce.

>> Yeah!

( cheering ) >> All right, stop!

>> All right, all right.

>> You guys realize you have well over half a ton on this bridge right now?

>> That's amazing.

>> Really impressive.

>> Look at that.

That is so solid.

That's amazing.

>> These bridges are both incredibly impressive.

But you know what?

There's a big decision to be made.

>> One of you still has to win, so we're going to peel off and decide who it is.

All right, let's review the criteria.

Had to span 20 feet.

>> Both of them did that.

>> They sure did.

They had to support all ten of us slash 11 of us.

>> Yeah.

>> Definitely did that.

>> That was excellent, yeah.

>> No problem, no problem there.

>> So we've got 100 points at steak.

How are they going to get distributed?

>> Well, I would feel really bad if it was winner take all, because both teams worked their guts out.

I was thinking along the lines of 60/40 in favor of the suspension bridge.

>> I was thinking more like 70/30 because the Red Team ran out of time and needed the extra help.

>> We had to step in there with a whole lot of people of the production crew to really get it done at the end of the day.

All right, you guys, we've come up with a decision.

>> I have to, with a lot of consideration, tip it in the favor of the Blue Team.

( cheering ) >> But there's more.

>> It's a little more complicated than that.

>> There's a "but"?

>> There's a "but."

There's 100 points at stake, so... >> We decided to also recognize the hard efforts of the Red Team, so the points split.

>> 70 points going to the Blue Team, 30 points going to the Red Team.

>> Go ahead and clap right now.

Everybody clap.

( applause ) Let's hear it for the Red Team.

>> I feel kind of gypped, actually.

I think the point totals should have been 60/40 favoring us just because there's a big difference between sawing these huge timbers and just twisting rope up.

>> This was a really important challenge for me point-wise, if I can be greedy for a second.

I've been in last place since we started.

>> I mean, I'm not too disappointed.

There's, what, ten other challenges... nine other challenges, so I know I'm not worried about my point total.

But I just think, as a team, overall, we did so much work, and I would have like to have seen a little bit more reward given.

But it happens.

>> I'm sure there's something I can't build.

I've yet to see it.

>> Tom may have finally won a challenge, but he's still tied for last place.

Kim holds on to the lead with 370 points.

All right, Deanne, here's a new challenge: describe the Design Squad Web site in ten seconds.

Go.

>> There are games, photos, new challenges, videos, quizzes, scoring updates.

>> Time's up.

>> Ugh!

Just go to pbskidsgo.org.