I do a lot of education cartoons. There’s a small but nice market for them, so I’m constantly on the lookout for little nuggets of curriculum for cartoons.
One day while perusing a math textbook I came across the Pythagorean Theorem. (If there are rock star theorems, this is definitely the Elvis of them.) After examining it and the accompanying illustration a bit, the triangle began to suggest a sales graph to me and this cartoon popped out.
I like to think that, at that moment, all of my old math teachers looked up for a moment and chuckled to themselves a little without exactly knowing why.