I had seen this proof before but I couldn't remember it, and this was a very concise and understandable presentation of it that made me happy.

Have many claps!

By the way, the graph is just fine, I had no trouble with it, but I am playing with matplotlib (free, open source) these days and, like, wow. It knocks out graphs like that in an instant. I suspect you'd have a lot of fun with it.