This paper is a simple theoretical paper expanding upon the circular flow diagram that traditionally is used in macroeconomics when examining GDP and the investment, saving relationship.  While the circular flow is well known, it seems never to be used when discussing the standard microeconomics topics.  This paper explains how the circular flow diagram can be extended to provide insight into micro issues such as demand and supply and the differences between perfect competition, monopoly, monopolistic competition and oligopoly.  The circular flow sketch has been tried in my MBA level econ classes with positive results.