Had a look through and really enjoyed the picture examples, can even remember some of those examples from uni.
And I see you are using vectorisation of hand drawn diagrams (maybe you write on a whiteboard and then take a photo and vectorise it). If you have an ipad I would recommend GoodNotes and a good stylus (maybe the Adonit Jot Script).
Due to a stupid oversight my iPad is stuck in storage somewhere a few countries over :( I really wish I could, but right now it's just me, white paper, a pen, a scanner and potrace. It's tedious, but workable :)
And I see you are using vectorisation of hand drawn diagrams (maybe you write on a whiteboard and then take a photo and vectorise it). If you have an ipad I would recommend GoodNotes and a good stylus (maybe the Adonit Jot Script).