Thanks, Zach. I totally agree with "It’s funny how you feel like you finally grasp the system then the next day you feel like you have no idea what’s going on again."... And yes, there are many systematizations and sub-systematizations and then many variants and dependencies. The difficulty of finding the perfect rules to systematize is, figuratively, like sleeping with a tiny sheet that when you pull it up to cover your chest, you leave your feet uncovered.