In more ways than one, as “rule” is a bit of a pun. I saw this in the Goulet Communiqué email I received today. Go here to see this interesting pen. From photo # 5:
It is primarily a fountain pen but also includes:
a Touch Screen Stylus
Under the stylus top are Phillips and flat head screwdrivers
on the barrel are a built in level, ruler and 3 different scale functions
It’s actually more than I usually spend for a fountain pen, but I might want one just for the usefulness and the novelty!