Maybe add [2014] to the title? It's pretty cool, though, not that often that one can read the way Peter Norvig is thinking.<p>Also, instead of "matches the last names of elected US presidents but not their opponents", would it be clearer to express "matches the last names of presidential candidates who got elected at some point, but not those who never became presidents" - or along these lines (sorry for the grammar). This is then a mutually exclusive list, and no interpretation problem.