I learned a little about Notan art this month since it was our theme for our ATC's. Notan is Japanese for light dark harmony. I also learned that they are a little addictive and it was hard to stop at just one or even two when making them.
Have you tried to do Notan before. If you haven't, give it a try. It doesn't need to be ATC size. I think I will have to try some other sizes and maybe colours too.