I'm proud to contribute my answer to my own Brain Teaser #2. You can read the solution here. I think many lessons are contained (and unwittingly, I migt add) in it for newbies and not just the details of Perl functions. This was a great exercise, if I do say so myself. I know I learned a lot from it and I hope others will too.
If my answer is not completely accurate, please feel free to chime in. If you haven't seen the problem yet, you can view it here.