The fun things I had to figure out included playing with least common denominators, creating a data structure that included everything I needed but which wasn't too complex, and fleshing out the measurements table properly after new user input.

Lots more fun than searching for a module would have been. And furthermore, how could someone build up coding mojo without retackling a problem that has already been solved? If I ever decide to contribute something completely unique and useful to the CPAN library, it will be because I have built up my skills solving things that have already been solved before.