I had a lot of fun working through this in the context of building mazes, e.g. http://weblog.jamisbuck.org/2015/11/28/upsilon-mazes.html http://weblog.jamisbuck

I had a lot of fun working through this in the context of building mazes, e.g. http://weblog.jamisbuck.org/2015/11/28/upsilon-mazes.html http://weblog.jamisbuck.org/2015/11/28/upsilon-mazes.html (not the author, just a guy who bought his book)