System usage is identified initially as a key element in generative art. This leads to the adoption of complexity, order and disorder as efficacious organizing principles in the comparison of several generative systems of art. The trace of definition of generative art is the preference the artist establishes in a system, that can generate a number of possible forms, and better than a single terminated form. The artist’s role is to build, begin or merely select the frame of procedures to generate possible expressions and, for this, the visual aspect may or may not be determining.