There is only a small number of notations that a software engineer can remember. Sooner or later, an engineer gets exasperated with so many alternative ways of describing a design, each with many fine details of expression, and gets on with the business of designing software. In this chapter, I summarize the design approach taken in this book, summarize the notations that we have reviewed, and provide a road map for using these notations. I sketch the spectrum from flyweight to heavy-weight use of the notations. The resulting approach is NYAM it is Not Yet Another Method; it is simply the gist of existing methods.

Section 23.1 summarizes the design approach taken in this book. Central elements in this approach are the distinction among the functions, behavior, and communication of systems, and the identification of an aggregation hierarchy in which reactive software design is embedded in a larger composite system design process. Section 23.2 summarizes all software design notations treated in this book and shows how they can be used in our design approach. The use of the notations is arranged in a sequence from flyweight to heavyweight use. Section 23.3 presents a method that starts with problem analysis and ends with the decomposition of the SuD. Section 23.4 shows the role that the notations can play in the system engineering argument and Section 23.5 discusses the difference between formality and precision, arguing that in software design we need precision before formality.