I agree: as much as I love the Fibonacci numbers, it's better to teach recursion with something like (say) implementing directory traversal (printing all files

I agree: as much as I love the Fibonacci numbers, it's better to teach recursion with something like (say) implementing directory traversal (printing all files under a current directory, like ls -R) -- some problem both where the recursive nature of the problem itself is obvious, and where it would be more awkward to implement without recursion. I'm looking forward to seeing what problems he thinks really merit recursion.