Biochemical pathways are abstract concepts developed by biochemists.
They represent series of interconversions of some substrate into a product. The traditional textbook pathway diagrams typically reflect a bias towards what the authors were mostly interested in, or the historical circumstances behind the discovery of the pathway. In reality these are of as much importance in cells as any others. Visualization is of prime importance in the understanding of metabolism and alternative views of a pathway may well reveal hidden properties. Additionally there are several pathways so complicated that there may be many ways of making intelligible 2-dimensional diagrams, although only one of these is usually presented in the literature.