If you pay attention to what the guy is saying, or if you look at the board he is using to display the information, you will notice something. No sharps between B and C and no sharps between E and F. This guy, in this one episode, is doing a very good job at explaining it. I have not watched the whole series. I am only saying that this episode is worth watching. I suspect the rest are pretty good, as he's explaining it much like I would in a visual medium. Edit: I am on the 2nd one and it looks like a very valid source. He is correct. Edit: I am done with the 3rd and he is still correct and doing a good job. I'm comfortable suggesting people watch the entire series, even though I'm not personally going to watch any more of it. I already know this stuff.