To a chemist, one of the many intriguing features of biology is the exquisite ability of biological systems to control pattern formation – from the stripes on the side of a zebra to the feathers of birds – and the extraordinary silicate architectures of diatoms, biological systems display spectacular examples of structural control across a wide range of scales. To do this, organisms have harnessed chemical processes in a remarkable way. In this lecture, Dr Sella uses a number of chemical reactions to illustrate these ideas. If all goes well, we may even bring an inorganic system to life. No mention will be made of the periodic table and no chemical background is necessary. Lecture given on 29 November 2007.