Ideas made here

(Fortune Magazine) -- If you happened to go shopping at the Wal-Mart Supercenter in Chardon, Ohio, about 30 miles outside Cleveland, you might spot two 50-ish guys browsing through the aisles, using their cell phones to take pictures of things like disposable-razor displays and bottles of detergent. Or you might not. "We're very discreet," says one of them, John Nottingham. "If people notice us at all, they usually think we're Wal-Mart employees."

Nope. Nottingham and his partner, John Spirk, run Nottingham-Spirk, the most successful industrial-design firm you've probably never heard of. What they're doing on their frequent Wal-Mart reconnaissance missions, Spirk says, is "looking for what's not there."

Craig Saunders (standing), with fellow inventors and one of the firm's hits, the SwifferVac.

More from Fortune

Will Mmmhops be a hit? NBA confirms L.A. Clippers sale to ex-Microsoft CEO Steve Ballmer FBI and SEC probe into Carl Icahn and golfer Phil Mickelson

FORTUNE 500 Current Issue Subscribe to Fortune

For clients like Procter & Gamble (Charts, Fortune 500), GE (Charts, Fortune 500), Black & Decker, Newell-Rubbermaid (Charts, Fortune 500) and Unilever (Charts), Nottingham-Spirk has created and patented 464 products, with combined sales of more than $30 billion. They include lots of clever stuff you might have at home, like the Crest SpinBrush, the Dirt Devil vacuum cleaner, the Sherwin-Williams twist-and-pour paint can, the SwifferVac, and a gadget called the SwivelStraight that lets one person put up a Christmas tree in less than a minute.

What sets this outfit apart from its competition is that Nottingham-Spirk doesn't stop at the concept stage. "Coming up with a great concept is wonderful, but it has to be workable," says Craig Saunders, a designer who's been at the firm for 24 years. "We don't necessarily set out to win design awards. Our goal is to help our clients make money."

Nottingham-Spirk's headquarters - in a spectacular building in Cleveland that used to be a Christian Science church - includes an engineering lab, where prototypes of new products are built and tested. Because Nottingham-Spirk also has an in-house marketing team, the firm can take its designs all the way from scratch-pad doodle to store shelves. This vertically integrated approach has helped sales skyrocket for so many clients that Nottingham-Spirk does no advertising and employs no sales staff to push its services.

A case history: On one of their Wal-Mart scouting trips in 1999, Nottingham and Spirk started thinking about electric toothbrushes. They were expensive, anywhere from $65 to upwards of $100. Also, "they were kept in glass display cases, so first you had to find a Wal-Mart employee, and then he or she had to go find the key to the display case," says Spirk.

The duo saw an opportunity. What if there were an electric toothbrush, with the plaque-busting power of the pricey ones, that sold for five bucks or less? And what if it came in a clear-plastic "try me" package that let you push a button and see the bristles spinning around? And what if it were displayed next to the regular old manual toothbrushes so that you could just grab one and toss it in your cart? Nottingham-Spirk designed the SpinBrush for a little company called Dr. Johns Products that was owned by Nottingham, Spirk and two other partners and later sold to Procter & Gamble. The Crest SpinBrush is now the bestselling electric toothbrush on the planet.

Of course, Nottingham-Spirk doesn't get all its great ideas from cruising the aisles at Wal-Mart. Many of its products were thought up in a conference room, with eight to ten designers sitting around a table. The process hinges on two kinds of meetings, held on an almost daily basis. The first kind is called a "diverging" session, where the designers get together and throw off as many ideas as they can think of, "from mild to wild," says Nottingham. "Mild would be, Okay, you want to improve this candy bar. You could change the flavor or add a different filling. Wild would be, What if the candy bar could levitate?" By the end the walls are covered with slips of paper bearing scribbles and sketches, usually 100 or more.

In the second round of meetings, called "converging," the ideas are judged. Each person around the table gets three index cards. One has WOW written on it. A second says NICE. The third says WHO CARES. Each idea is considered, and the person who thought of it gets a chance to promote it. Then, at exactly the same moment, everyone holds up the card that best reflects his opinion. "If everyone holds up a WOW card, you know you've got something," says Nottingham. A consensus of WHO CARES means the idea gets tossed. "The hard ones are where everyone votes with their NICE card. Nice isn't good enough."

It's essential that everyone vote at once, he says, because then "there is no alpha dog. No one is able to sway anyone else. In most meetings people tend to defer to one or two people, either because they're high-ranking or because they're particularly persuasive. But when you're trying to innovate, you don't want that. That's death."

Can a NICE ever turn into a WOW? Sure. Take, for instance, the SwivelStraight one-minute Christmas tree stand. The basic design consists of two interlocking parts, a half-dome that fits on top of another, deeper half-dome. You wrestle the tree into an opening in the center, then step down on a pedal that rotates the two parts in a ball-and-socket movement until the tree is standing straight, then take your foot off the pedal to lock it in place.

"It's very simple," says designer Craig Saunders. "But it only got a NICE in the meeting. When that happens, it says to me, Okay, why is this only NICE? What can we do to make it a WOW?" Saunders kept tinkering and refining, adding, for example, a self-regulating water tank similar to those on dehumidifiers, "so you don't have to crawl under there to add water to the bucket." Saunders's colleagues gave the improved version a WOW. That was in 2002, and Emerald Innovations, which makes the SwivelStraight, has since sold almost a million.

At every stage in a new product's birth, Nottingham-Spirk brings in focus groups to comment on it. Saunders, who has invented or improved everything from medical devices to bicycles, says he's gotten the most useful insights from focus groups by asking them what makes them mad. "If you ask, 'What is it about this that really pisses you off?' you get great answers."

Focus group folks loved the Swiffer mop for quick cleanups around the house, but got exasperated because it couldn't pick up anything chunkier than dust. "So if you spilled cereal or dry dog food or jellybeans on the floor, you had to go get out the vacuum cleaner," says Saunders. "People really hated that." So, thought he, why not have one appliance that could do both kinds of tasks? First he duct-taped a Swiffer mop and a vacuum cleaner together. Then he had several focus groups try it. Then the lab built a SwifferVac prototype. Before long, P&G found itself in the vacuum cleaner business.

Some clients need to be won over to Nottingham-Spirk's ideas, especially when they concern a design that has been the same for decades. Paint cans, for instance, had been metal cylinders for at least a century. You needed a screwdriver to open one and a hammer to close it, and pouring the paint was a sloppy business. When Nottingham-Spirk designed a plastic paint jug with a tidy spout, a screw top, and an easy-to-grip handle, client Sherwin-Williams said, "Huh?"

First, critics said the new paint jug would be hard to stack in warehouses and stores, so engineers made the prototype wider and more stackable. "Then someone said, 'Okay, but how durable is it? What happens if you drop it?' So we took a bunch of them up on ladders and dropped them," says Nottingham. "They bounced."

The package has won design awards and more than tripled the number of retail outlets that sell Sherwin-Williams paint. "This kind of situation is where it's really crucial to be able to be able to build prototypes," Nottingham says. He and Spirk learned that more than 30 years ago, when they started the company as graduates of the Cleveland Institute of Art's industrial-design program. Spirk went to a library and made a list of every company in northeastern Ohio that manufactured anything. One was an enterprise called Rotadyne that made rotation-molded bedpans. "Rotation molding was a process we had just studied pretty extensively in school, so we actually knew quite a lot about it," says Spirk. "And one thing we knew was that it was very good for making toys."

So they designed some toys, made some prototypes and went calling on the folks at Rotadyne. "Luckily for us, the president of the company at that time was a young guy with four little kids at home, so he was very receptive to the idea of making toys instead of bedpans," says Nottingham.

So receptive, in fact, that the company changed its name to Little Tikes and let Nottingham-Spirk develop a line of playthings, including a little roadster called the Cozy Coupe Convertible, which turned out to be a big hit with toddlers. When Spirk and Nottingham first came calling, Rotadyne's annual revenues stood at about $1 million. In 2005, Little Tikes, now owned by MGI Entertainment, reported revenues of $250 million.

Now, that's a WOW.