The set of knowledge that a polymath has may differ completely from another polymath, but at their cores, they are extremely similar.
This is because of the drive, curiosity, and openness required to become pi or comb-shaped, as opposed to just T-shaped.
For instance, do you think that someone like Leonardo da Vinci looked at a problem he was unfamiliar with and said, “Someone else will take care of that, I’m going to take a nap”? Probably not.