The connection diagram and state graph are shown first, because they are visually oriented. The informal specification describes both the external structure and the observable behavior of the system. The terminology is chosen to be uniform and fairly precise, without being pedantic. It is intended to give a quick impression of the system. For details you should turn to specifications expressed in one of the formalisms below.
Many systems have various pictorial representations.
Choosing a schematic diagram for a system raises similar problems as choosing a name. Here are some of the criteria we consider. The Zoom link brings up a picture that is magnified by a factor two in both dimensions. The Fig link brings up the xfig source of the picture. This may not be the case for some generalized specifications, which must first be properly instantiated.