Figure 1. Representation of the R ₄ network.

(A) This schematic of the R ₄ artificial chemistry network is composed of metabolite “strings” of a up to a maximum length of four, and all allowed reactions between them. (B) The reaction list for the R ₄ network. There are four reactions that represent the exchange of mass with the environment (r₁-r₄) – one for each metabolite – and four reactions between the metabolites (r₅-r₈).