we use an inch and a half so you've got three layers of glass, and you can dance on it or whatever el else. fluid, as a disco bar near the four seasons on mission street for all you younger people. and they've got a lineup to get in there, one of those. and they have this dance floor that's covered with this inch and a half glass. and lights underneath. and it's very impressive. >> i think it's the indian reservation just built a projection of glass over the grand canyon. >> yes. >> and it has a glass floor, i understand. >> yes. >> read anything about that? >> i showed the picture to my wife, and she turned white, and says i'm not going. >> [laughter.] >> so like 2,000 feet straight down on a glass floor, wow. >> but it's perfectly safe, and all that. and that's kind of the excitement of glass, is being able to see through it, except there is an additional state requirement, ubc, that says, wait a minute, this is all fine and well, but i don't want you slipping on this. and so a certain percentage of that then has to be either sand blasted, or have like little dots on it, like the floors