Today is the 100th birthday of a famous mathematician. Part of his fame comes from his work on mathematical biology, namely his ideas about patter formation in biological systems (such as the stripes of a zebra). One interesting result he obtained was that such patterns can be formed by diffusion processes which are usually known to be “smoothing” and hence, destroying patterns. But when two diffusion processes are coupled, they may be able to form patterns. The mathematician wrote just one paper on this topic but this is considered seminal in this field; it is the work The Chemical Basis of Morphogenesis and the author is Alan Turing. Happy birthday! (Reading through the links, you’ll find, that Alan Turing has made some more valuable contributions to mathematics and computer science but I just wanted to highlight this one which is usually not the first one that is associated with him.)