Here's some fur, fiber, and oil cloning in action. The concept is very simple. You can "clone" any image, and clone brush you choose changes the output. Furry cloners pick up the colors of the original, oil does the same but adds depth, straight cloners *directly* copy the source pattern, and so on.

I messed around with fur and hair brushes in Photoshop a lot, but I think I am going to switch to Painter for all texturing since all of my PS plugins work in Painter (terazzo, KPT, and so on.)