This brilliant BBC4 documentary kicked my ass. It talks about chaos theory, fractals, patterns and loads more. The punchline is that chaos and order (pattern) are beautifully and inextricably linked. That even the simplest equations and mathematical formula, when fed back into themselves (this bit is key) cannot be examined far enough back to make accurate predictions about where the formula might end up- hence sand dunes, cows spots and nature in general looks similar but not the same. Fractals are part of this- and a guy called Mandelbrotz pretty much invented these while he was working at IBM- the whole thing is linked nicely to something called 'self similarity' which is like branches and rivers and out blood vessels and loads of other stuff. Really good but hurry click here to watch it before the 24th.