That's a question David Schwartz has asked about casino carpet. As the director of the Gaming Studies Research Center at the University of Nevada, Las Vegas, Schwartz's job is to contemplate all things casino. Carpet so fascinates Schwartz that he devotes an entire gallery on his blog, the dieiscast.com, to casino carpet. There, he writes: "Casino carpet is known as an exercise in deliberate bad taste that somehow encourages people to gamble."

That may be true, but how? Schwartz says he doesn't know, but there are almost as many theories as there are carpet designs. One thing he has noticed, is that, while it differs from property to property, casino carpet has a common element: It tends to be festive. Or busy, depending on your point of view.

"I'm not sure (about its purpose). I've been trying to figure that out. Sometimes it's very clear it's involved in the theme of the resort," Schwartz says. "You can look at carpet and see how they've carried some of the design elements into the ceiling. You can tell a lot of thought was put into it."

Paris Las Vegas and Wynn Las Vegas are two examples; his favorite carpet is at the Peppermill in Reno.

"It's a space scene with a rainbow in it," he says.

Others, though, are more of an enigma, the kind of carpet that leaves a person wondering, "what?" he adds, though he declined to give examples.

"I don't want to pick on anybody," Schwartz explains.

One theory he has heard is that casino operators don't want patrons looking down. They make the carpet so unappealing, or garish, that people want to look anywhere but at the floor. That doesn't hold water to Schwartz.

"That's a weird theory because people tend to look at whatever's eye level," he says.

What does make sense to Schwartz is the camouflage idea. Multicolored carpet with tight patterns tends to mask dirt and stains. And if anything needs masking from dirt and stains, it's a casino carpet.

Mike Nolan, general manager for El Cortez, agrees that much thought goes into the selection of a casino's carpet. Recently, the El Cortez installed new carpet, and for the first time, put a full pad under it, he says.

In the past, casinos didn't use carpet padding because when money carts rolled over it, the carpet bunched up and took on a wavy look. Now that machines are mostly ticket-in, ticket-out, carts full of coins aren't necessary, Nolan says.

Carpet brings the property's design elements together. As to why it's so decorative, Nolan says that's no mystery.

Casinos are large; a carpet with one solid color would accentuate the room's size and make it look, and feel, like a warehouse.

"It's a wide open space, and you don't want it to look like a data processing center," Nolan explains. "You want something with more of a party or a lively type of look to it."

Carpet tends to last five to seven years in a casino before it needs replacing, Nolan adds.

Yes, some are loud or colorful, Nolan admits, but it could be worse. Casinos could use what they did years ago: linoleum.