Robert Indiana’s eight-foot Cor-Ten ONE Through ZERO (The Ten Numbers) (1980–2003) is a monumental example of the artist’s long-held fascination with the power of numbers. The series of sculptures perfectly encapsulates Indiana’s multifaceted engagement with the symbolic and formal aspects of numbers, a subject that stands as one of his most important iconographic themes. Indiana, who credited his enduring interest in numbers to the formative experience of moving households multiple times as a child, living in twenty-one different homes by the age of seventeen, has noted that “our very lives are structured around numbers . . . Everything we do is reckoned on numbers.”  Their extensive potential as a subject matter lies in their universality; understood across cultures, they engender multiple references and significances, based both on individual experiences and shared cultural meanings.
Numbers first appeared in Indiana’s work in the late 1950s, when he began applying stenciled numbers, which served primarily as abstract titles, to his sculptural assemblages. As Indiana expanded his use of numbers their functions grew to include locating paintings in series such as The American Dream, and serving as personal signifiers that added thematic content to individual works while establishing threads throughout his oeuvre. Numbers as a subject in their own right became a signature motif of Indiana’s painting in the 1960s, their forms inspired by the robust Arabic numerals of an old printer’s calendar that Indiana found in his loft in Coenties Slip in early 1961. The artist carefully shaped and refined these numbers, isolating them for portrait-like images in works such as his 1965 Numbers, a group of ten large-scale canvases representing the numerals one through zero. In these works the numbers, with their mix of fleshy serifs, voluminous curves, and flat, hard-edge lines, are treated with a centrality and individuality more commonly associated with human subjects. The cardinal numbers are also central to his Decade Autoportrait series (1972–77), which represents a symbolic portrait of his life during the decade of the sixties.
Indiana’s numbers have an inherent sculptural quality, which the artist was able to fully explore in his number sculptures. ONE Through ZERO was first executed between 1980 and 1983 as a series of eight-foot painted aluminum sculptures, a special commission that was donated to the Indianapolis Museum of Art. He later created several series of number sculptures in different scales and finishes, including the eight-foot Cor-Ten ONE Through ZERO. Indiana had worked with Cor-Ten previously; it was the material he chose for his first monumental sculpture, a 12-foot LOVE (1970), and his 12-foot AHAVA (1977), created for the Israel Museum in Jerusalem. Also known as weathering steel, Cor-Ten is a material that takes on a patina from its environment over time. A Cor-Ten sculpture’s surface layer develops and regenerates continuously when subjected to the influence of the weather, eventually developing a rich velvety rust-colored appearance.
The diverse exhibitionary possibilities of the Cor-Ten ONE Through ZERO are illustrated by the various ways they were displayed in cities throughout Spain and Portugal between 2006–08, and in Milan during the 2008 exhibition Robert Indiana a Milano. The Numbers, displayed on important boulevards in Madrid, Valencia, Bilbao, and Lisbon, and on the Corso Vittorio Emanuele II in Milan, became part of each particular urban landscape, giving the public a unique local experience of the same work.
The Cor-Ten number sculptures also make a powerful statement when displayed individually. A Cor-Ten SEVEN stands at the entrance of the Portland Museum of Art, serving as a symbol that reaffirms the physical location of the museum at Seven Congress Square, as well as of the museum’s commitment to adding iconic artworks to its collection. As a public sculpture, a landmark, and a tourist attraction, the sculpture helps to define the city.
Indiana’s Co-Ten ONE Through ZERO is a celebration of numbers as universal emblems that transcend the barriers of language; they are embedded with personal associations for the artist, yet are able evoke an array of individual meanings among the public. Furthermore, the qualities of Cor-Ten give the number sculptures a distinctive quality in that the works, while transforming the environment in which they stand, are simultaneously being transformed by that environment, which leaves its mark by contributing to the weathering of the Cor-Ten, thus becoming part of the history of the work.
 Marius B. Péladeau and Martin Dibner. Indiana’s Indianas: A Twenty-Year Retrospective of Paintings and Sculpture from the Collection of Robert Indiana. Rockland, Maine: William A. Farnsworth Library and Art Museum, 1982.