The other day I complained to Christos Papadimitriou about the name of the complexity class PPAD. He answered that he had not realized beforehand that one could see a reference to his own name embedded into it. Surprised, I asked: Really? Yes, really, he said. The first person to point it out was a reviewer. In fact, he added, if people were not allowed to define complexity classes by giving them names that were subsequences of their last name, then it wouldn't be fair to him!