If there’s any A-to-Z I think I could improve on, it’s the first I wrote, in the summer of 2015. But it takes a couple attempts to figure out how to do anything. While there’s essays I think I could improve, there’s still quite worthwhile ones. Among them is Graph, which I think was my first essay to touch on graph theory. For a while in my academic career it looked like I might move into graph theory, so I’m always glad for chances to talk about it. This essay just lays out what graph-theory type graphs are.