Reference 11 has been added after Equation 10, to point the reader to where to find information about phi limits was first discussed. Repeating this information here would complicate the paper. The lines Phi = 2^(1/3) and 4^(1/3) in Figure 1d have now been explained.
Produces a dynamic model for chemical evolution rather than traditional deterministic, static, systems that requires centralised information to direct evolution, such as a constant gradient.