This applet displays a reaction-diffusion system. Begin exploring by using the "Preset" choice at the bottom - and the "Restart" button below it - to see some of the possible configurations. Configurable parameters include a number of manual colour-map controls (on the left) - and six main parameters of the reaction-diffusion system (on the right). Take care if using the other controls on the right. They are usually very sensitive. The model is a cellular automaton, based on the [von-Neumann neighbourhood]. It is based on the Gray-Scott model, and was taken from John E. Pearson's Complex Patterns in a Simple System - Science, 261, 189, 9 July 1993. More details about the type of system used can be found at the [Xmorphia web site]. Toroidial boundary constraints are appled, so the images will tesselate seamlessly. Optionally, a bumpmap technique is employed to give the images a sense of depth. The "saturated" state in the automaton can often be a chequer-board pattern. This is largely an artefact of the use of the use of the von-Neumann neighbourhood. I have also constructed a version that uses the [honeycomb neighbourhood] - and there the chequer-board artefacts vanish.