RIO DE JANEIRO (AP) — Jeff Koons' "Balloon Dog" and Henry Moore's "Archer" are among some of the world's most iconic sculptures competing for space at a new museum exhibition where one of Alberto Giacometti's signature figurines appears to stride boldly into the room.

It would be a world-class show if the pieces weren't copies made of Styrofoam, using the same techniques for making the floats in Rio's Carnival parades.

The exhibit "End of Matter" by Mexican artist Damian Ortega celebrates artisans who make Carnival floats, bringing them out of the stifling hangars where they labor anonymously. In a space transformed into a workshop inside Rio's Museum of Modern Art, the artisans saw, slice, sand and drill away at giant blocks of Styrofoam while visitors look on.

"It's an homage to work, to the creative process," said Ortega, one of Mexico's best-known contemporary artists. Ortega got the idea for the show when he lived in Rio from 2012-2013 and came across a larger-than-life-sized bull's head of Styrofoam that was abandoned on the train tracks.

"It was a survivor from Carnival," he said in a telephone interview from Mexico City, adding that the encounter inspired him to visit a samba school hangar where such pieces are made. "It was beautiful, so amazing, and the idea stuck with me."

The 47-year-old Ortega has shown his work in numerous countries, and currently has sculptures in the shape of graffiti tags included in the "Panorama" exhibit at the High Line urban park in New York.

Ortega's show in Rio opened last month with a few finished sculptures and a towering pile of Styrofoam in the middle of the exhibition space. The foam has gradually shrunk as seven artisans churn out pieces under his tutelage. The aim is to have the cavernous hall filled with sculptures and all 2,000 kilograms (4,400 pounds) of foam blocks used up when the exhibit ends on June 14.

The copies, which museum officials calls "homages," are all true to the size of the originals. As a result, the Styrofoam "Balloon Dog" stands at more than 3.5 meters (11.5 feet) tall, just like the original of polished stainless steel.

The show also includes replicas of pieces by unknown artists, such as a grimacing stone carving made by Mexico's native Olmec people some 2,500 years ago. Next up is an 8-meter- (27-foot-) long reclining Buddha from Southeast Asia, which the artisans will coax out of the massive rectangular blocks using heated metal wires, long knives shaped like scythes and combs with nails for teeth, among other customized tools of the Carnival trade.

Rather than their original colors, or the eye-popping hues of the floats, the pieces are plain white, covered in a layer of flat paint that disguises any seams where bits of foam are glued together.

While it's largely the same work the artisans do for the samba schools, working conditions at the museum are very different from those inside the giant hangars in Rio's derelict port area.

For starters, the museum has air conditioning, something the sweltering hangars lack. But the workers have to keep a lid on the noise level at the museum, dialing down the vigor of their scraping and sawing and playing samba songs on the radio at a whisper.

Still, the museum working hours are a lot better.

"Here we have to arrive at a certain time, and the museum closes at a certain time," said Charles Rocha, 39, who has been a "carnavalesco," or Carnival artisan, for two decades. "At the samba schools, there's no such thing as a shift. When Carnival gets close, we work all day, all night and are at it until our arms give out."

Daniel Soave, a 34-year-old who usually works for the Emperatriz Leopoldinense samba school, said the show has helped legitimize his work and has given the Carnival arts the recognition they deserve.

Brenda Valansi, co-founder of the annual ArtRio art fair, hailed the show as "interesting, really very cool," but said she is disappointed about the artwork's eventual fate.

Museum president Carlos Alberto Gouvea Chateaubriand noted the artisans' time there is limited, and said when the show ends, their pieces will go the way of all Carnival floats — to the garbage.

"I understand the concept and it makes total sense, artistically," said Valansi. "But I would really like to have that Giacometti in my living room," she said, referring to the sculptor's long and lean "L'homme qui marche I."

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