By Stephen T. Romano
July 14, 1980 12:00 PM

A sudden rainstorm washed away the Mona Lisa. Commuters walked callously across a Rembrandt. Unthinkable? Not to Boston-based artist Robert Guillemin, who as “Sidewalk Sam” paints classics on concrete canvases.

Sidewalk Sam has transformed more than 300 street corners all over the world into ephemeral artworks. “It’s fragile,” Sam says of his art. “It’s associated with the earth, associated with a moment. And past the location, past the moment, it has no application. It’s as temporary as a flower.”

A typical Sidewalk Sam blossoms in one day and measures 8’X10′. The crouching artist is invariably surrounded by curious onlookers. Friendly waitresses, he reports, often trot out of neighborhood bars with vodka martinis in coffee cups. “A lot of children come up,” he continues, “and say, ‘Mister, that’s good. You ought to be an artist.’ ” Sam draws in pastels, copies from postcards, prints and art books and never attempts original works. His biggest effort—which took three days to complete—was a 3,600-square-foot logo for Boston’s Convention and Tourist Bureau that he drew in Copley Plaza two years ago.

Born in Cambridge, the son of a Harvard biophysics professor, Guillemin displayed enough artistic ability when the family moved to Chicago to win a scholarship to that city’s Art Institute. He went on to earn a master’s degree in fine arts at Boston University before spending two years at the Ecole des Beaux-Arts in Paris.

A divorced father of twin boys aged 16, Guillemin, 41, lives in suburban Needham and supports his hobby with commercial art and lecturing. Seeing himself as a sort of Johnny Appleseed of the art world, he says, “I would love to wander all over the face of America creating these pictures.” One future project is a sidewalk rendition of Michelangelo’s Sistine Chapel.

In 1973 the Boston police threatened to arrest Guillemin for defacing public property. (He has since been granted official permission to draw almost anywhere he pleases.) In seven years of sidewalk sketching, he’s never been assaulted, verbally abused or had any of his equipment stolen. “Dogs,” smiles Sam, “are my harshest critics.”