The mirror tool splits the image into four sections, you paint in one section and it mirrors those actions, filling in all the other sections automatically. It's one of my favorite tools and the end results look cool, most days.
Ah yeah mirroring, that's a funny creative tool. There's a fine video out there with a lot of mirroring.
It's Just Whatever...
I zone out for hours working on this stuff. Music's on. It's one way to feel good.