Artist Marilyn Zwak developed the imagery from designs on prehistoric Native American (Hohokam) artifacts found at the site during the excavation for the freeway. She surfaced the forms with adobe, a traditional southwestern building material made from dirt, clay, water, and hay. By the completion of the project, Zwak and her two assistants labored more than 4,000 hours and applied 150 tons of adobe to the overpass columns and towers.
After the major elements of Zwak's design were in place, she invited area residents to imprint their own designs and objects in the freshly laid adobe. The variety of inlaid images and items range from hand prints, personal initials, abstract patterns and scribbles to household mementos such as tools, keys, coins and remnants of clothing. This was the Phoenix Public Art Program's first design team project.