 Now, petroleum and gas is a different game because that is only in sedimentary rocks and it's only in sedimentary rocks of a certain age. And then what you do is you do seismic, which is a type of geophysical measurement where you send a great big machine out to pound the ground as hard as they can and you put sensors out to measure the waves produced by that pounding when they come in. So in some geophysical course or short video, you'll hear about the SP and the L waves that travel at different velocities. If you take all those and process them, you can get a cross section through a sedimentary strata full of a bunch of squiggly lines. And in those squiggly lines, the people that make a lot of money working with petroleum companies, they can see what looks like something worthy of drilling a hole into. And if they do hit a big petroleum play, the amount of money they can make, at least currently is quite huge, so they're happy to drill lots of holes. So you go to places like Texas and Saudi Arabia, there's drill holes all over the place because we have this voracious need for more petroleum. And the price still stays high, so we're still doing a lot of that.