Implementation [of phyllotaxis model]
It is convenient to consider a line of discrete cells, much as in a continuous cellular automaton. With a concentrations list c, the position p of a new element is given by Position[c, Max[c], 1, 1]〚1, 1〛, while the new list of concentrations is λ c + RotateRight[f, p] where f is a list of depletions associated with addition of a new element at position 1. In the main text a Gaussian form is used for f. Other smooth functions typically nevertheless yield identical results. Note that in order to get an accurate approximation to a golden ratio angle there must be a fairly large number of cells.