…both sides. When you have a picture that's symmetrical, this side's somehow the same as the other side. But after some thought, Professor Weil has given a perfect definition of symmetry. A thing is symmetrical if you can do something to it and it appears…

…apparently at least. A vase can be symmetrical that particular way or in other ways. How can you define it? Well, Professor Weil, a mathematician, gave an excellent definition of symmetry. It's this. As I am left and right symmetric, that means that if…