Laurie DeWitt/The Gazette David Whiteis has worked on his bubble ring invention for the past six years. He hopes it will some day be used to entertain marine animals in zoos and aquariums.

David Whiteis thinks the bubble rings he creates are actually quite pretty. And he spent the last six years perfecting a contraption that will form them.

Now he hopes the rings will also find their place in aquariums and zoos everywhere.

For more than six years, Whiteis, 43, has labored to recreate a childhood talent forming underwater bubble rings -- tiny discs of air that rise and expand, creating a tantalizing, glassy doughnut-shaped bubble. He hopes they will one day become a staple toy for fish and water mammals at zoos and aquariums.

"People can watch as dolphins and polar bears play with it," Whiteis said. "That's what I'd most like."

Every few seconds, the small Plexiglas device resting at the bottom of the hexagonal fish tank spits out a tiny disc. The delicate ring of trapped air floats to the surface -- then pop! It's gone.

Then the device pushes out another one. It floats up to the surface and pops. Whiteis' device could become mesmerizing.

The bubble ring has already appeared at the National Aquarium in Baltimore, where the dolphins, whose toys often consist of old basketballs and empty plastic milk jugs, had something new to play with temporarily, Whiteis said.

In the past four years, dolphin trainers at the aquarium have used the bubble ring device in the 18-foot deep dolphin tanks a half-dozen times, he said.

"They watched the bubbles going up to the surface," said Sue Hunter, director of marine animals and animal programs for the National Aquarium. "Then they came up and started biting the bubbles. ...It was fun while we had it here."

Aquarium staff also put a smaller device into the tank with the seals and fish, she said.

"That one was neat," she said. The animals "investigated the bubbles."

Hunter said she thought the aquarium might be interested in buying the device if it was "easy to put into the water and indestructible to the dolphins."

His device also made an appearance in the shark tank at the Tulsa Zoo and Living Museum in Tulsa, Okla., in May.

The dolphins, "as playful as puppies," love the bubble rings, he said.

Trainers love them, too, since many solid toys pose a hazard to the animal if they break during play. The bubbles, Whiteis said, present no such problem.

Whiteis initially invented the bubble rings device to simulate a trick he learned as a child blowing bubble rings with his mouth in the pool.

After selling the rights to his first successful patent on computer software, he began looking for something else to develop and keep for his own.

He started in 1999 with his first bubble ring model, a tilting, U-shaped design that an electric pump would fill with air, sending bubble rings up through the water. Except, it didn't quite work that way.

Six years later, after agonizing over design problems, he came up with a circular design.

"I about had a nervous breakdown," he remembered.

One night, in Sept. 2004, he dropped the new circular prototype into the tank, adjusted the air pressure and watched, amazed, as it finally worked.

He woke up his sleeping wife, Kasia, to show her.

"I remember that," Kasia said laughing at their home on Thursday.

But Kasia said she did not mind. But, she added, it would have been different "if he had woken me up to tell me it didn't work."

Now Whiteis is the proud owner of three patents on his bubble ring designs and one legally complicated patent covering the general process of making bubble rings.

The U.S. Patent and Trademark Office in Alexandria, Va., issued more than 180,000 patents last year. About 90 percent of those were for utility, or "invention," patents, a department spokeswoman said.

Whiteis' bubble ring device is not the first strange idea to come out of his creative mind.

On his computer, he has saved a five-page list of possible inventions. He guards it closely. Any one of those ideas could hit the jackpot, he said.

But after some coaxing, he divulges another idea: a palm-sized tactile toy for patients to use while at the dentist.

The small block of wood would have raised engravings of animals, he said. Placed inside a silk bag, the patient would try to guess what animal it was by tracing the outline with her fingertips.

"It distracts you," he said, while being careful not to say too much.

"It could be taken if I don't pursue it," he said.

So far, he has not sold any of his bubble ring devices, but he hopes he might with the help of a new Web site, www.bubblerings.com, created by his wife, who works at home as a freelance Web designer.

Being married to a hobby inventor requires a special kind of patience, Kasia said.

"It's been hard, going through phases," she said. You think "something is going to come through, but nothing comes out of it."

Persistence is key, and that is something of which her husband has a lot, she said. Otherwise, she said, "he would have given up years ago."