While I like the image itself, it feels a little on the dark side, which may cause some printing issues, and the structure of the wolves themselves still aren't ready for prime time, i.e.: another revision is in store, thus, making this the third repainting and the current back a work in progress.
The shapes overlaying the wolves represent the sacred geometry found on Da Vinci's Vitruvian Man. Plans are to expand this a bit more as well.