Andrew Sella answer how the zebra got its stripes.
In Rudyard Kipling's Just So story, the Leopard got its spots when the Ethiopian painted them on with his fingers. In the real world, the answer to the question of where patterns come from is not so simple. While the processes of natural selection provide us with a mechanism by which patterns such as spots or stripes might be retained from one generation to the next, the question of how the patterns are programmed is something of a mystery.
In this lecture, a series of ever more complex and spectacular chemical reactions will be used to show how very simple ideas in chemistry can lead directly to the idea of feedback, the crucial insight given by the mathematician Alan Turing, that provides a plausible mechanism that causes complex structures and patterns to emerge as if from nowhere.