During the past decade, much im-portance has been placed on the structure of mathematical systems. Structure has been the byword in the construction of texts and courses. For this task the framework of geometry has been found to be quite acceptable at the secondary level. The axiom system of Euclidean geometry is examined in depth, but usually very little attention is given to other axiom systems. Occasionally axiom systems are discussed per se, but examples are usually too difficult to develop (such as non-Euclidean systems), too limited in de-velopment (such as a finite geometry), or too trivial to create any interest.