Figure 7. Reaction-diffusion (RD) simulations of pattern formation compared to actual biological patterns. A: Some stable states that RD systems can generate. B: Some two-dimensional simulations produced by a simple Turing model. C top: Actual and simulated shell patterns produced by Meinhardt's (2003) RD model. C bottom:Actual and simulated fish skin patterns produced by Sanderson, Kirby, Johnson, and Yang's (2006) RD modelon fish skins. From “Reaction-Diffusion Model as a Framework for Understanding Biological Pattern Forma-tion,” by S. Kondo and T. Miura, 2010, Science, 329, p. 1618. Copyright 2010 by the American Association for the Advancement of Science. Reprinted with permission from AAAS. 755 HALLUCINATIONS AND CORTICAL PATTERN FORMATION