An open-plan office is primarily defined by the absence of fixed walls — a single shared acoustic environment for all employees and all work types. An agile office is defined by the provision of a genuine range of workspace environments — open collaborative zones, enclosed focus zones, enclosed meeting zones of various sizes — in proportions that can be adjusted as team needs evolve. An open-plan office without modular enclosed acoustic infrastructure is not an agile office; it is simply a flat floor plan. Agility requires both physical variety and the infrastructure to reconfigure that variety without construction.