The diagram compares the traditional department with a self-organised circle and highlights their fundamental differences. In a department, responsibility lies predominantly with a manager. A circle, by contrast, distributes responsibility and leadership tasks across several roles, which are carried out collectively by the members.
Whilst departments are managed by higher-level authorities, circles organise their collaboration largely independently. They decide autonomously on roles, internal structures and the formation of sub-circles. Furthermore, an employee is usually assigned to only one department (home circle), but may participate in several circles at the same time.
Source: See here