Chapter 5: Two Dimensions and Beyond

Section 4: Substitution Systems and Fractals

[2D substitution systems with] non-white backgrounds

The pictures below show substitution systems in which white squares are replaced by blocks which contain black squares. There is still a nested structure but it is usually not visually as obvious as before. (See page 583.)

Image Source Notebooks:

From Stephen Wolfram: A New Kind of Science [citation]