 If you're a bat, a nocturnal mammal looking for flying bugs, you make a noise, and you listen to the echo that comes back off of the bug, and then you know it's out there and where it is. Humans have adapted similar sorts of technologies to look for oil. So in this case, being done in the ocean, this is ocean water along here, and we have a ship going along, and it makes a noise. It uses an air gun. They used to use dynamite. And the noise is bounced off of various layers down below and then is listened to back here. And by looking at how bright and how long and other things about the arrival, you can learn a lot about the rocks that are down underneath. And people do this both on land and in the ocean, and they're looking for those special places where oil is accumulated, and we can go in and drill into it and get it.