Closely studied and later widely copied by other architects, these projects linked late-modern Southern California architecture to the latest experiments in minimalist art and sculpture. Still, Lumsden's designs, produced for a successful corporate firm, were the work of a pragmatist, and put a premium on efficiency. As Daniel Paul puts it, "the reversed mullion saved money on aluminum and used standardized, inexpensive components."
In a tremendously creative period in the early 1970s, Lumsden produced a series of designs that replaced placid, unbroken skins for more complex cylindrical and rolled shapes. Lumsden referred to the technique as "extrusion." It found its purest expression in designs for a convention center in the Swiss city of Lugano and a proposed addition to the Beverly Hills Hotel. Neither project was built.
Lumsden was soon directing the firm's design work on a series of large industrial commissions, including the sprawling Hyperion wastewater treatment plant in El Segundo and the Donald C. Tillman Water Reclamation Plant in Van Nuys, finished in 1985. Both projects rank among the most underrated designs in post-war Southern California architecture, in large part because so few members of the public have seen them in person.
Not all of Lumsden's work from this period was acclaimed. The Marriott Marquis Hotel in San Francisco, completed in 1989, was a rare and widely criticized turn toward historicism in Lumsden's body of work. It stacks a jumble of Art Déco forms into a 39-story tower, quickly nicknamed the "jukebox" by San Franciscans.
