Thanks for reminding me of the O(log(n)) algorithm. I had forgotten about it. Just added this algorithm to the lecture slides. I <3 the internet.

I start with the recursive algorithm because it follows directly from the definition F(n+2) = F(n) + F(n+1). I also think there's a big schism in programmers: between those that think recursively, and those that are of a more iterative bend. I'm in the former camp, probably owing to the fact that my first programming language was Scheme.