Tic-Tac-Toe, Complete

I've been watching Lisp tutorials lately. I guess I have an odd idea of fun. While the tutorials demonstrated how to use Lisp, they glossed over some points that I thought they should have spent more time on. I'm not going to write yet another tutorial. There are enough already. But if I were going to write a tutorial, here are some of the things I'd want to discuss.

The whole activity of programming revolves around creating abstractions to solve problems. Lisp is an excellent choice of programming language because it offers more opportunities for abstraction and less resistance to abstraction than other languages. While you are programming, you are constantly making choices about which abstractions to use.