The joke started like this:
Me: I have more swords than there are students in this class.
Student: You know what this means, right? You can finally have your own private army.
Rather than arm my students and send them out into the world to right wrongs and such, I designed a shirt instead. Anyone is welcome to get one - current and former students, colleagues, friends, family, even people who just wicked like the shirt.
Note: I am not making a profit from these. I just really want to have my own and decided to let others in on the fun too.