The Leopard Spots

How did the spots on a leopard, the stripes of the zebra or tiger, or the patterns on sea-shells, form? Is there some simpel general framework which can explain these beautiful patterns? Yes, these patterns are called Turing structures, named after the Bristish mathematician who came up with a model to explain such structures. Some chemical systems, when maintained far from equilibrium display oscillatory behaviour. When the chemical waves of such a reaction are allowed to diffuse through a medium at different rates andthe resulting pattern stabilised, one obtains Turing structures. Later in this course we will look at many other interesting far from equilibrium systems, some of them showing cyclical behaviour.