"There are some fantasies about us," Humberto Campana, the soft-spoken half of the São Paulo design team known as the Campana brothers, acknowledged during a recent visit to New York. "One journalist said we were leaving the favela" — meaning one of Brazil's ubiquitous urban shanty-towns — "for Sweden." His younger brother, Fernando, chimed in: "Somebody said that we used to go to the Amazon and cut down trees!" Humberto: "And that we were gathering garbage from the street." Again, Fernando: "People think we are freaks or junkies, that we take a lot of drugs or do whatever. I haven't, we haven't — "

To clarify: The Campanas do not live in a favela and never have, although their Favela chair is a bona fide classic. Its seemingly jury-rigged construction from countless slats of wood suggests both homegrown shacks and a game of Jenga gone seriously haywire. They don't have anything against Scandinavia, but their hearts belong to São Paulo, where they live and work in the intimate Santa Cecilia neighborhood. ("Everything is very local," Fernando says, "I feel like I'm in a country town.") As for the Amazon, they love flying over it on one of their jaunts to, say, Design Miami, where last December they collaborated with glassblowers at a thronged outdoor demonstration; to the annual Milan furniture fair, where they display their latest outré creations — like the kaleidoscopic Sushi chair — for the top-shelf manufacturer Edra; to Athens, where they're now at work on a top-down reno of a 1960s-era hotel; or to New York, where they are the guest curators of "Campana Brothers Select," currently on view at the Cooper-Hewitt.

When it comes to trees, the Campanas are more likely to plant them — as they did not long ago on their farm outside São Paulo, where their mother still lives and where they recently installed 15,000 examples of native flora. Although the brothers have made chairs, sofas, and tables out of such ready-made materials as bubble wrap, carpet underlays, garden hoses, sailing rope, cardboard, and shards of glass, they don't typically Dumpster dive. Regarding illicit substances: "I need to be in a very clear state to do this," Fernando insists. "When I am in São Paulo," Humberto adds: "I wake up at six o'clock and I am in the studio. I need discipline." Fernando puts the final kibosh on the notion that, for the Campanas, life is a 24/7 carnival: "One day someone called me for dinner at eight o'clock; I was already sleeping."

But it's not hard to see why the brothers have inspired so much conjecture and fantasy. Ever since they burst onto the international design scene as part of the landmark "Projects 66" show at MoMA in 1998, their steady output has provoked — perhaps more than any other design oeuvre of the present day — waves of ardor, bafflement, and even, at times, revulsion. (In the wake of "Projects 66," a New York Times critic dismissed them as "clever and indulgent.") In other words, they're not afraid to push buttons.