Here’s a very good presentation on the thinking of the Pythagoreans, from The Rising Tide Foundation (I have seen a few of their presentation on History which I found interesting; this one came up as a result of my subscribing to that channel, which I do recommend). It is detailed, albeit somewhat necessarily - due to time constraints I would think - less detailed than might otherwise be the case. It covers a lot of ideas re harmonics, the five Platonic solids, and myriad relationships that follow from this line of ancient thought, including various geometric connections within the periodic table of elements. As a way of at least beginning to understand both the depth of thinking of the Pythagorean school of thought and the relevance of such thinking to much of JPF’s works, especially those that reference musical examples, I think this presentation is indeed worth the time invested in watching it 
