The author describes how he used to teach a unit on food webs and ecosystems using actual food webs as models. However, the models used by the author tend to be either too simplistic or too complicated for his students. A few years ago, he solved these problems by making up his own food web, complete with invented plants and animals. The model has allowed him to control the complexity of the food web. In this article, the author describes how to prepare this unit. (Contains 6 figures.)