"Traffic signals, a boat.
The simplest traffic signal you can think of is a stop sign.
It's a signal that you have to stop to be careful.
So you don't crash into other cars or people at an intersection.
If we move up from that, then you get the blinking red lights which tell you to be careful at that intersection and then we move up another rank and we get the three colored traffic signals that we all are familiar with.
Red, yellow, green.
The interesting thing is, although it's an international convention, red, yellow, green, the colors have different meaning for different people and this isn't just from country to country, but from city to city in some places when the traffic signal turns yellow cars slow down and stop before they get to the intersection.
On the other hand, in other places, when it turns yellow cars speed up.
And in some places I've seen cars even entering the, the intersection after the yellow has turned to red, they continue going as if they didn't see it, they pretend they didn't see it.
Well, anyway, now we've got another thing going on with the traffic signals.
I've seen some traffic intersections where you have the red and the yellow and the green.
But in addition, you have arrows.
And I was very, very confused when I saw an intersection traffic signal with a big red light on and a green arrow at the same time, does the red mean stop or does the green mean go having them side by side? Really confused me.
But I thought if I stop, then the cars behind me will feel upset.
So I proceeded with caution through the intersection.
One more thing that's interesting about the traffic signals is they're getting skinny.
Now, the old traffic signals used to be kind of fat.
They'd be several centimeters thick.
But these days the lights they're putting on, well, they must be led lights because they're really thin.
I think they save a lot of energy and they're certainly a lot slimmer looking.
So traffic signals are getting more modern all the time."