BPMN and Business Process Management

The analogy between this representation and swimming pools is a useful one. You can imagine a process swimming down a lane, and changing lanes as need be to perform an activity, within a pool. The pool can be considered a ‘pool’ of resources. There are occasions when the process needs to jump to another pool, because it has different resources needed to complete the activity.
This is particularly apt where there is a need to describe B2B processes, where different organizations pass messages among one another to perform an activity. This is described in the next section, Modeling B2B Message Flows.
A Pool Can Represent Many Things
A pool can represent other things besides an organization, such as a function (something that the organization performs, like Marketing or Sales or Training), an application (or computer software program), a location (a physical location in the company), a class (a software module in an object-oriented computer software program), or an entity (representing a logical table in a database). It can only represent one thing, but that thing comes from this ‘heterogeneous list’ of different types of things.