The poster for Spoleto Festival 2013 is a low-key, geometric image open to interpretation.

It is called “Angled Ring” by American minimalist artist Robert Mangold. Superimposed are a pale red pentagon made with pastel and a black circle drawn with pencil. Faint compass lines are discernible. At the shape's center is a void that can be filled with the viewer's imagination, said Spoleto Festival General Manager Nigel Redden.

The poster was unveiled Tuesday at Bob Ellis Shoes on King Street.

The work, made in 2011, is part of a series of “Ring Paintings” by Mangold. Redden said he has long admired Mangold's minimalist aesthetic and thinks this piece represents the festival well.

“I love the idea of conflicting geometric ideas that somehow can come together,” Redden said. “In some ways that's what we do.”

It's available for sale at the Spoleto Festival box office, located at the Charleston Visitor Center, 375 Meeting St., or by calling 579-3100. It costs $25.

A window display contest will be expanded this year beyond King Street. Public voting begins May 24. The winner gets two tickets to the festival finale.

As Spoleto posters go, this one is subtle and simple. Past years have featured works by Maya Lin, Jim Dine, Chuck Close, Frank Stella and David Hockney, among many others.

The last time geometry played a central role was in 2008, when Bridget Riley produced the festival's first horizontal poster featuring blue, green and white wave shapes.

In 1989, conceptual and minimalist artist Sol LeWitt created an imperfectly formed brown cube set against a yellow background.