I'm amazed at how well the results work, and how easy he makes it look. This is a classic example of how something can seem obvious in retrospect, yet wasn't.

I'm amazed at how well the results work, and how easy he makes it look. This is a classic example of how something can seem obvious in retrospect, yet wasn't. This could easily be scaled up or down to any size desired. It might even be able to work on a protractor.