I think it's interesting that their brief doesn't provide any citations for the proposition that Mayo identified these four discrete guideposts for determining

I think it's interesting that their brief doesn't provide any citations for the proposition that Mayo identified these four discrete guideposts for determining whether a claim is directed to an unpatentable abstract idea. In fact, I'm not sure Mayo can be read as doing much at all beyond breaking the walls between the three judicially created exceptions: abstract idea, law of nature, and natural principle. After Mayo, they're sort of just one big (unworkable) exception. Boy, I hope I don't have this wrong since I have my Patent Law final exam tomorrow morning!