The computer provides a significant enhancement to artists' ability to work with the underlying structures of art works and art systems. New concepts and constructs have become available to us in ways that enable new forms in art. One such significant concept is generative art (Brown 2003). Here, the artist specifies their intentions and a computer program builds the art work from that specification. Many new possibilities arise from this development and a number of challenges also present themselves. One such challenge is to find appropriate methods and notations in which to represent the specification of the art work. These specifications amount to programs providing that they completely describe the generative processes involved.