And I have 100 of them.

You'll hear a train in moment that they don't react to.

The fun part is, I'm going to the Boston metro, and playing a pong game inside the train on the ground, right?

...

40 Watt incandescent lamp

100 Watt incandescent lamp

200 Watt incandescent lamp

No, your flashlight is meant to illuminate.

For us, we're very facile around electricity.

The light bulb has burned out.

Did you build this train, Dad?

So I have one light bulb there.

I'm going to number them one through 100.

But I think you get the point.

So what's our question?

Here are the cables coming up into this light fixture.

As you might guess doing so would take a huge amount computation for even the most modest scene.

Lightrail, tram

Car Phone

Zoom in on the tram.

Train again? !

tramway.

36, 49, 64, 81, and 100.

I gotta tell you, I'm a protective parent.

the red and yellow SBahn.

train license sure?

A little bit of differential, but not much.

The response to a bad idea

Well, let me actually just draw them.

So the first light bulb is light bulb one.

The fifth light bulb would have been on and it'll stay on.

So the first pass, I switch every light bulb.

Four times four is 16.

Car

Stop the train!

I'm on a train.

Streetcar.

Tramway.

Or I could say, I know that I'm going to switch light bulb 51, because 17 is a factor of 51.

So for example, if we're looking at light bulb eight.

lasers, portable X Rays, shielding for nuclear reactors, compact discs, hybrid vehicle motors,

The train arrival is to the second!

I'm an employee of the train company.

Streetcars run on electricity.

But the pay off is really enormous.