I like to think of generative art as the creation of pretty images from short descriptions and a source of randomness.
Quadtree Grammars are a form of formal grammar that can generate 2D images and ASCII Art . Generative Art with Context Free Grammars explores the use formal grammars to create sequences of turtle-graphics instructions. This method was also used for the Isometric Flower series.
Other collections include isometric renderings of voxel structures like Intersecting Stacks and Snowflake-Like Symmetries . Isometric Octrees generalize Quadtree Grammars to generate 3D structures.
Poisson Trees explores randomly generated structures that look like trees.
Errors and Glitches collects unexpected images resulting from software or hardware bugs.