Spanish artist Jaume Plensa's "Nomade" sculpture was installed this week in downtown Des Moines' Gateway Park. John and Mary Pappajohn purchased the piece to loan to the Des Moines Art Center, soon to be added to the museum's permanent collection. "Nomade" is made of randomly arranged stainless steel letters, painted white and arranged in the shape of a person sitting with knees drawn up to the chest. Roger Machin of the Chicago-based firm Methods and Materials was in charge of the installation and described the process.