How to compute Fib(n) in log(n) time

Yeah, it's only logarithmic in the number of matrix multiplications, so the title is a bit hyperbolic, but I just thought the technique was cool.

I got there via: http://blog.sigfpe.com/2008/11/approach-to-algorithm-paralle...

Which was perhaps more informative as to the actual technique, but had less obvious wow factor. My bad.