Typical solutions of 1D model A. Distribution of ligand (top) and receptor (bottom). B. Solution of the model for α = 0. Red dots represent terminal positions of individual axons, originating at various points in retina. If the case α = 0 the map is completely random, since all the chemical cues are multiplied by zero in Eq. (1), and, therefore, cannot contribute to the solution. D. α is very large. Solution represents perfect ordering of axons in SC in the order of increasing density of receptor. This is because the chemical cues are extremely strong in this case, much stronger than noise. C. α = 30. At the intermediate value of α solution is a compromise between chemical signal and noise.