DENVER -- Nobody will steal Greg Boom's lawn ornament -- unless the thieves have a big truck and a lot of time on their hands.

The retired John Deere supervisor turned sculptor crafted a 4-ton stone cairn in the front yard of his rural Denver home. It took Boom 1 1/2 years and hundreds of hours of back-breaking labor to build the egg-shaped masterpiece.

But to Boom and his wife, LaRue, a lot of work is a small price to pay for a lifetime of enjoyment.

"We like the natural look of the stone. You can't buy it at Wal-Mart," LaRue said.

The Booms officially will unveil the cairn and other works of art scattered throughout their Rustic Hills yard Tuesday to the Federated Flower Art Club of Cedar Falls. About 15 members are expected to tour the property at 9:30 a.m.

The couple's perfectly manicured landscape -- combining an array of native flowers, grasses and transplanted flora along man-made walking paths -- is enough to warrant a spread in Better Homes and Gardens. But it's Greg's art meticulously placed throughout the property, especially the eye-catching cairn, that's worthy of the cover.

"We have never thought of this as a showplace. It's just where we live," LaRue said.

On second thought, the couple know their place is special.

"Cars drive by real slow now," Greg said.

Greg doesn't consider himself an artist, just someone who likes to stay busy. Everything about the Boom's acreage says otherwise.

The house is filled with intricate wood carvings he's been doing since the early 1970s. Stone carvings of insects and barbed wire spheres dot walking trails.

And, of course, the cairn exceeding 5 feet tall he built stone by stone. No mortar, pins or glue was used. It's completely dry stacked. There was some math involved, figuring out differing outside diameters of each piece to achieve the egg-shaped appearance. After each calculation, he used a 4-inch hand-held grinder to shape the stones.

It may look like a giant Weeble, but the cairn's weight, shape and interlocking stone construction method ensures it won't fall over. There were no instruction manuals to follow.

"Maybe I have a little more talent than others," Greg concedes, while not sounding pretentious.

"I enjoy making things and challenges, and having things no one else has. I bet there's not another in Bremer County," he added.

Greg's right. In fact, there's most likely only two others in the state. Greg was inspired by one of them.

A cairn is a non-naturally occurring pile of stones, often used to mark the summit of a mountain. They're also used mark paths or a burial site.

British landscape artist Andy Goldsworthy is famous for making them into works of art. He's built several around the world, including two in Iowa -- one at Central College in Grinnell and the other at the Des Moines Art Center.

While visiting their daughter in Johnston, the Booms visited the art center while Goldsworthy was building the cairn in 2002. He was fascinated by the workmanship and the beauty of the 8-foot-tall sculpture

"I thought I could do that, and I thought it was pretty cool," Greg said.

When Greg told his wife that he wanted to build a slightly smaller replica for their yard, she wasn't surprised.

"He's always talked about doing a grand project like this for years. He just gets inspired and does it," LaRue said. "There's always a project.

"He works all the time out here. I have to remind him he's retired," she added.

The Booms made five or six trips with their truck and trailer to Stone City and spent the day rummaging through scrap piles of limestone to find material. The same place Goldsworthy got his stone.

It cost the couple about $1,000 in materials to build the cairn. But if Greg paid himself $20 per hour, the cost would be astronomical, he said.

"If I knew how long it would take, I would not have started it," Greg joked.

Laura Burkhalter, assistant curator at the Des Moines Art Center, was in charge of their cairn project. She said Goldsworthy was assisted by about 10 professional stone masons.

The cairn is one of the center's most popular pieces, Burkhalter said. When she heard of the Booms' replica, Burkhalter was impressed.

"It's really flattering someone would make the effort to do that, it must have been a labor of love," she said.

It was.

And the Booms hope others fall in love with it as well.

"It's for our enjoyment, but if someone stops by to enjoy it too, that's great," LaRue said.

Contact Matthew Wilde at (319) 291-1579 or matt.wilde@wcfcourier.com.