The real core of what being an engineer is. You have a scientific basis, but when you don't have the science, you put in some bugger factors, some sa… - Douglas T. Ross

Computer-aided design is not automatic design, although it must include many automatic design features. By automatic design we mean design procedures which are capable of being completely specified in a form which a computer can execute without human intervention.

There are certain basic, known principles about how people's minds go about the business of understanding, and communicating understanding by means of language, which have been known and used for many centuries. No matter how these principles are addressed, they always end up with hierarchic decomposition as being the heart of good storytelling. Perhaps the most relevant formulation is the familiar: "Tell 'em whatcha gonna tell'em. Tell 'em. Tell 'em whatcha told 'em." This is a pattern of communication almost as universal and well-entrenched as Newton's laws of motion.

(SA) combines blueprint-like graphic language with the nouns and verbs of any other language to provide a hierarchic, top-down, gradual exposition of detail in the form of an SA model. The things and happenings of a subject are expressed in a data decomposition and an activity decomposition, both of which employ the same graphic building block, the SA box, to represent a part of a whole. SA arrows, representing input, output, control, and mechanism, express the relation of each part to the whole.