I've done bits and pieces on using Materials Room stuff for various effects, including furry skin textures. For this sort of radial effect, look at the Tiles node. You can get round or elliptical tiles, and you might be able to do something with thick mortar, large scale, and the offset inputs. There's also a softness control. Yes, it's possible to draw a circle with math nodes, but this Tiles node method can be a lot simpler to adjust. The softness you would get at the boundary is very smooth. It might look better if you add some low-level noise. A Clamp node would then clip the output to the 0-1 range that's needed to control a blender or transparency or whatever. In this case, with the way V3 is mapped, a more elliptical pattern would be better, which would stop the wrap reaching so far around Vicky's back. It can help a lot having a texture, not connected to anything, as a positioning reference in the Materials Room.