2012-03-14
Explanation
In this comic, a professor is lecturing about cardioids -- heart-shaped curves produced by certain polar equations (r = a(1 - cos theta)). He complains that the naming convention is confusing because the shape doesn'''t really look like a heart. This seems like a reasonable mathematical gripe about misleading terminology.
The punchline comes in the final panel, labeled "Earlier...," which reveals the professor'''s true motivation. He made a bet with a colleague that he could say the word "testicloid" forty-seven times during a single lecture. The implication is that he'''s not genuinely frustrated with naming conventions at all -- he'''s deliberately steering the conversation toward shape names that sound like body parts in order to win his bet. The humor lies in the contrast between the seemingly earnest academic complaint and the juvenile real reason behind it.
The votey panel continues the gag, with the professor saying "Testicloids are usually couched in polar equations," showing him working hard to shoehorn the made-up term into his lecture as many times as possible to win that hundred-dollar bet.