VENICE - A few of the nearly three dozen works in the Bruce Nauman show opening at the Venice Biennale are not the original works themselves, but second editions refabricated with the permission of the owners.

Among them are the Vices and Virtues neon ringing the top of the U.S. Pavilion, and, at the Universita Iuav di Venezia at Tolentini, Pink and Yellow Light Corridor (Variable Lights) from 1972 (pictured).

The creation of an "exhibition copy" allows everyone to have their cake and eat it, too. The owner gets the prestige factor of the work having been shown at the Biennale without having run the risk of damage by transporting it (neon is especially fragile). And exhibition organizers, in this case the Philadelphia Museum of Art, can have the works they want represented.

Some of the refabricated pieces - made in workshops in Chicago and Venice - were recreated especially for Venice, and others had been previously re-created.

Obviously, refabrication makes the case that the value of a particular work is the idea (though refabrication happens under the supervision of the artist, often with the same craftsperson who created the original work).

What happens to these officially endorsed imposters once the show is over?

Sometimes they are destroyed, said Alice Beamesderfer, the Philadelphia Museum of Art's head of curatorial affairs, while others live on to travel once again when a museum makes a request to borrow.

The concept of refabricating might be antithetical to a world that traffics in the concept of authenticity.

Then again, Beamesderfer points out, contemporary art sometimes uses materials that leave you no choice.

She remembers a piece at the museum that used real potatoes. After a while they just needed to be replaced, she said.