Splash some color on big rocks, plant them on a hill, call it art and you really set yourself up for the "My-kid-could-do-that" reaction.

Since New York-based sculptor Jim Hodges has done just that at Walker Art Center, it seemed appropriate to ask him to explain what's up.

Hodges' rocks are huge, by the way. There are four of them, each about 5 or more feet in diameter and weighing between 8 and 13 tons. Fine-grained, dull-brown granite boulders, they sit in a cozy circle midway down the grassy slope just west of the Walker and overlooking the Minneapolis Sculpture Garden.

From a distance they might suggest the abandoned eggs of a prehistoric monster, or perhaps something more excremental. A closer encounter reveals shimmering colors -- iridescent pink, gold, lavender and blue -- on their inward-facing sides.

"I never think about who else could do it," said Hodges, 54, who seemed a little taken aback by the "my kid" question. As acting chair of the sculpture department at Yale University, he's not accustomed to having his authority questioned, let alone his integrity. Then he squinted, grinned thoughtfully, and rose to the occasion.

"The casual application of color to a natural form is something I'm very much taken with," he said. "So in a modest way, they can be related to a child applying color to a stone."

The idea came to him last year during his first trip to India. He was struck by the way colorful flags and bright powdered pigments -- saffron, crimson, indigo, pink -- are used in religious rituals and prayer. Inspired by the vivid hues, he sought a way to introduce them into the landscape of contemporary sculpture.

"The intention is located in the arrangement of the forms and how color appears on them," he said. "That's my job and what distinguishes these boulders from the casual gesture of putting color on a rock."

During a visit to Hodges' studio, Walker director Olga Viso spotted his drawings and a little tinfoil model of the sculpture. She's co-curating, with the Dallas Museum of Art, a retrospective of Hodges' work booked to open in Minneapolis in February 2014. She felt the rock sculpture would suit the Walker's hillside -- if it was the right scale to anchor a 4-acre site and if it could be engineered to survive Minnesota's winters.

"He created it with the Walker in mind but we waited until it was finished" before purchasing it, Viso said.

Steel-faced rocks a challenge

While the piece looks simple, its construction was a challenge for the foundry in upstate New York where it was built. The main problem was how to fasten to the rocks contoured slabs of colorful, highly polished stainless steel that are up to an inch thick.

Throughout his prolific career, Hodges has made a point of making his work appear casual and unfussy, whether it's made from broken glass and mirrors or light and rocks. In this case, the stainless steel had to fuse seamlessly with the rock face. That required making casts of the rocks, carving away the sections to be steel-faced, molding the metal plates, attaching the steel with hidden screws and pins, sealing the edges and polishing the surfaces to new-car gleam.

Finding the right rocks was tricky, too. Hodges wanted natural boulders whose worn surfaces would look timeless.

"I don't want to get in trouble with the boulder people," he said wryly, but after scouting the quarries of St. Cloud he ended up with rocks from western Massachusetts.

Meanwhile, to support the 40-ton sculpture, the Walker had to pour concrete bases and reinforce the roof of the parking garage under the hill.

The sculpture's apparently casual placement is in keeping with the Walker's evolving ideas about the slope. When the museum expanded in 2005, it planned a formal landscape linked to the Minneapolis Sculpture Garden. Budget constraints shelved those designs, so the center invited community suggestions for a site that has become a popular gathering spot for concerts, film screenings, dance performances and just hanging out. From June to September the center treats its Open Field as an area where programmed and spontaneous activities happen.

Schoolkids often end their Walker tours by climbing to the top of the hill and rolling down, a childhood pleasure that Walker officials are loath to inhibit with art or landscaping. Plans under discussion include some "edge treatments" and possibly a trail from the Sculpture Garden up the hill and perhaps into the building.

"We want to keep it largely open," said Viso. "We see it now as much more of a public commons."

Last week visitors were already strolling among Hodges' boulders as their shiny-steel sides mirrored the sky and showed quavering images of the Walker and the downtown skyline. As the sun set, the panels seemed to toss poetic bouquets of ever-changing light onto the scene.

Touching art is off-limits in the Sculpture Garden, but the boulders naturally invite climbing, of course. Hodges winces at the thought.

"I prefer not," he said. "I mean it is art. But it is an outdoor experience, so what can you do?"

Then he waxed philosophical.

"I was inspired to work with boulders out of reverence and love of the material itself," he said. "These stones have been sitting on this planet for 400 million years, in their indifference and perfection and singularity. So it's important to me that whatever I add be appropriate and reverent. In the end, it's all about the boulders."