When using BPMN$,$ a pool has two representations: The first $($normal$)$ representation displays its internal details, so it is possible to create connections directly with the objects inside the pool. In contrast, the second representation hides all its internal details. These representations are best used when the pool represents an external process and the modeler has no k ledge of its internal workings. You may communicate$-$ with this pool using message flows.This second pool representation is known as aswimlaneblack box white box external entity