A technique, useful in the teaching of computer science, is to use programming notation to build small working models of the topic being described. A successful notation, in this application, will provide concise, but fully accurate, working models. Both Scheme and J excel in model building. Suppose we wish to use recursive definitions, in a divide and conquer fashion, to model both recursive and iterative processes. This technique is often used when analyzing the fibonacci sequence. We use this example to illustrate not only modeling techniques but also illustrate the expressive power of Scheme and J to describe recursive and iterative processes and continuations.