In the first application, the messages have no apparent pattern. Every object may send any message to any other object. If the messages left visible trails, these trails would eventually draw a woven mat, with each object connected to every other. Figure 4.1 Communication patterns In the second application, the messages have a clearly defined pattern. Here the objects communicate in specific and well-defined ways. If these messages left trails, the trails would accumulate to create a set of islands with occasional bridges between them.
Oop diagram
