Fig. 5. Sequential appearance and patterning of spots with mathematical simulation. (A) The resolution of the model led to the formation of a primary migrating cell midline. (B) The redistribution of these cells, via chemotaxis, led to the formation of spots, whereas laterally, new cells started to migrate. (C) The lateral expansion of the pattern was due to migrating cells under both chemotaxis and arresting factors. (D) At the end of the simulation, the hexagonal pattern occurred all over the modeled domain. Cell density is represented in false colors.