Yale Law's Commencement is today. Although square graduation hats have been around since the 16th century, there have continued to be improvements in mortarboard technology; for example, a quick Google Patents search revealed that three Chicago inventors filed mortarboard patents in the 1930s, and Ohio-based Thomas La Maida filed three patents in the 1950s. And maybe I should have a graduation cap cover?
Unfortunately, I was unable to locate any scholarship discussing this important topic. But congratulations to all my graduating classmates!