Panorama of London open plan office in late 1990's. Open plan is the generic term used in architectural and interior design for any floor plan which makes use of large, open spaces and minimizes the use of small, enclosed rooms such as private offices. Open plan offices have existed for a long time. However, prior to the 1950s, these mostly consisted of large regular rows of desks or benches where clerks, typists, or technicians performed repetitive tasks. Many different companies are experimenting with designs which provide a mix of cubicles, open workstations, private offices, and group workstations.