For David Smith, steel was the quintessential modern material of the 1950s—a symbol of progress, movement, power, destruction, and brutality. Following the Cubist model, Smith combined various industrial pieces, often discarded scraps, into an open network of abstract forms. In the early 1950s, he began conceiving his sculptures as parts of titled groups, which allowed him to explore multiple permutations of a single theme. Tanktotem is a series in which Smith incorporated boiler parts and cylindrical steel tank parts that he purchased from a catalog. With their characteristic upright forms, these works straddle the boundary between the human figure and abstract sign.