Murals have always been among the more popular forms of public art. They can spruce up a city block or give restless teenagers a way to express themselves. They're usually associated with urban renewal projects, but every now and then, murals are commissioned by organizations or businesses trying to enliven their own image. Such is the case with a new mural going up along I-94 in St. Paul, which celebrates the state's most famous mascot and the serene beauty of the prairie in the heart of the city. Minnesota Public Radio's Chris Roberts reports.