Is there a way to define a TikZ shape using TikZ code rather than PGF? I'd like to have a gear shape (and some others) that I can use as a node and add text to it, have arrows go in and out of it, etc, just as one can with predefined tikz node shapes. Now, there's a nice example of drawing a gear with TikZ in https://tex.stackexchange.com/a/58735/29445, but I have no idea how I could turn that into a node shape. Creating node shapes (and some other answers) simply suggest using PGF -- however, since I'm just starting out with TikZ, I'd rather not learn another set of commands (especially since PGF seems kind of low-level to me).
Essentially, my question is: is there any shortcut? Or do I simply have to know PGF in order to use TikZ?