Very nice. I gave a lab assignment like this once! It's a great way to learn Prolog.
It's a lot of fun to work through, other prolog resources can be a little dry
No worries. A great philosopher once wrote:
"There is a theory which states that if ever anyone discovers exactly what your HN handle is for and why it is here, it will instantly disappear and be replaced by an HN handle even more bizarre and inexplicable."
"There is another theory which states that this has already happened..."