I am not a mathematician. During my training as a physicist I developed some competence in fields like geometry, algebra, and calculus, but I do not have the ability to create mathematics. I even find it really hard to read the mathematical literature. So I am probably missing out on exciting methods that may be useful for my present research in computer vision.

Last summer I decided to brush up on my understanding of projective geometry and found some great YouTube videos. The mathematician Norman Wildberger has a large collection of 10-minute videos in which he enthusiastically and very clearly explains math concepts and methods. He stands in front of a paper sheet attached to the wall on which he has written formulas and drawn geometrical diagrams. He points to details with the tip of an old drum stick.

I have become a huge fan and check his YouTube channel regularly. He inspires me, and teaches me great insights and useful methods. And I also like his fundamental approach. He dares to ask the questions of a 7-year old. And he answers them. For example, he developed a new approach to geometry called rational trigonometry that is not based on distances and angles, but instead on simpler entities that he dubbed *quadrance* and *spread.*

I do not know how he is regarded by the professional mathematical community, but that is inconsequential to me. He has created something that I value highly. And that assessment is shared with some other people judging from the 200,000 times his videos have been watched.