Jim Al-Khalili's utterly mind-blowing programme explored theories of patterns in nature and the application of mathematical principles to naturally-occurring phenomena. It started with Alan Turing's writings on morphogenesis (the differentiation of cells in the early stages of development) then went on to Mandelbrot Fractals, Chaos Theory and Darwinian evolution all in one fantastic hour. The idea that complex self-organised systems arise from simple rules induces us to look again at the inherent and totally unpredictable patterns in nature. A great programme - well done BBC4.
Have a look at this fantastic Mandelbrot Fractal apparently nicknamed 'God's Thumbprint':