A system can be classified in many different categories. Systems can be categorized according to size or scope. Dorner says that the world consists of many subsystems, and it is wise to think about them from the context of their interactions with one another.  A system may be part of much larger system; it is a microcosm. Or it might be large enough to encompass several smaller systems; it is a macrocosm. For example, a project may be part of much larger endeavor, such as a program with the former being a microcosm and the latter a macrocosm.
Another categorization is the distinction between a static versus dynamic system. A static system is one where little or no change occurs. A dynamic system is where change occurs quite regularly. For example, a project might be very stable or it might have to change its approach constantly.
Finally, a system may be categorized as closed or open. A closed system does not interact with its environment to adapt to changing conditions. An example is a project that fails to change its plans in response to a cutback in funding. An open system adapts to changing conditions. An example is a project that adjusts its plans to reflect a cutback in funding.
Of course, a system can fall into three categories at the same time. A system can be a microcosm that is open and adapts dynamically. An example is a project that changes its plans to reflect a change in scope.
 Dietrich Dorner, The Logic of Failure , Perseus Books, Cambridge, MA, 1996, p. 5.