Effects of the spatial and temporal ordering of events on the behaviour of a simple cellular automaton

Using a simple cellular automaton model, I demonstrate that the timing mechanism for events on different sites within the model can have a large impact on macroscopic model predictions. This implies that modellers must consider how to iterate their models so as to produce timing of events which match the biology of the problem rather than allowing a potentially unbiological timing (and hence an unrealistic model) to be imposed unintentionally by computational expedience. I discuss how to achieve this and suggest that model presentation should always describe the timing mechanism fully in order to allow others to repeat published simulation experiments.