Hey, I'm Nate from Design Squad.

My neighbors have a cat.

I love this cat, and it's fun to feed the cat when the neighbors go on vacation.

But I have to go all the way up the stairs to the third level twice a day, every time I feed the cat.

Now, I don't want to do that.

So my solution is to build a cat feeder.

I've decided the best way to do this is to make kind of a vertical clothesline system so I'll pull on the string, and up will go the cat food.

Now it's time to make a prototype, or a kind of a test version of the most important mechanism in this whole system.

Now, that's the part where the cup of cat food will tip over the top, into a chute that dumps it down into the cat food bowl, where the cat can eat it.

If I'm going to make a vertical clothesline, that means I've got a pulley down at the bottom, and there's also a pulley up at the top.

Now, if I want to make something that's flipping the cup over the top, dumping cat food into the bottom, I need an axle for that pulley to spin around.

So I need to attach an axle to this railing.

That axle needs to be parallel to the railing.

I'm thinking a good way to do this would be to use a C clamp.

This is a C clamp.

The C clamp has a handle on it that could serve as that axle, and that'll be really easy, because it means I don't have to put any nails or screws into the railing.

I can just clamp it right on.

Let's build a prototype.

I've got this roll of fishing line.

But instead of using it as a roll of fishing line, I'm just going to use it as a pulley.

So we can just take it, and now we can put it onto an axle that we can clamp to things.

Awesome.

Since I'm not going to be actually wanting to take fishing line off of the spool, I'm just going to tape over it.

Now I've got our C clamp positioned with its handle acting as an axle that's parallel to the rail just like we wanted.

So let's put a little rope over it and see if it looks like it could work.

Very nice.

We just attach the cup to that spool and we should be in good shape.

But I'm kind of seeing something here.

That axle wound up a lot further away from the rail than I thought it would.

That's not even going to dump it onto the railing.

That'll just come back down on my head.

But the good thing about using a C clamp is we can take it off and put it back on in a different spot that might work a little better.

Now, this is the great thing about making a prototype.

The purpose of the prototype is it's an in-between stage where we can try things out and see if it's going to work.

Because if it doesn't work, it's not a big deal.

I think we're ready to test.

(laughing) Well, that worked pretty well.

I mean at least we got it mostly in the bowl.

So our chute might need a little bit of redesign work, but, hey, I think we're ready to go to the final build.

So tune in for next time when we take this up to the third level to actually feed the cat.