Following the poor sales of Action Office I, Propst and Nelson went back to the drawing board, and sought to create the next-generation, "Action Office II". For several years Propst and Nelson fought over what kind of work environment they believed would best suit a corporate office worker. Unable to come to an agreement, Nelson was eventually taken off the project. With Nelson gone, Propst was free to explore his concept of an office that was capable of frequent modification to suit the changing needs of the employee, without having to purchase new furnishings. He wanted to allow the employee a degree of privacy, and the ability to personalize their work environment without impacting the environment of the workers around them. Propst recognized that people are more productive within a territorial enclave that they can personalize, but also require vistas outside their space. His concept was the "back-up," a two or three sided vertical division that defined territory and afforded privacy without hindering the ability to view or participate in happenings outside the space.