Madison Square Park, the 6.2-acre swath of green in Manhattan’s Flatiron District, faces some challenges after opening its third season of outdoor sculpture exhibitions. Initially teamed with New York’s Public Art Fund, the Madison Square Park Conser-vancy launched an independent contemporary sculpture program in June 2004. To date, its one-artist exhibitions have featured Mark di Suvero, Sol LeWitt, Jene Highstein, and now Ursula von Rydingsvard, whose work is on view through February 28, 2007. While all of these artists work in an abstract visual language, future projects are planned that deviate from a Modernist-derived idiom. Sound artist Bill Fontana, Roxy Paine, whose pieces focus on nature gone awry, and Charles Simonds, who creates imaginary civilizations in clay, are all slated for forthcoming shows. Madison Square Park has become a gallery without walls, where art is installed in landscaped “rooms” across the lawn. The program is trend-setting in its installation practice, relying on museological models for displaying massive sculpture. The test for the park’s programmers is to continue to attract major sculptors while bringing first-rate sculpture to a varied viewing audience.