Here is Irradial done on a black tile, with a bit of fractalization. Again, I wanted to keep the string simple so that I could just enjoy drawing the tangle. I also wanted to experiment with using Copic markers to shade around each section. It didn’t quite get as dark as I wanted, so then I added black charcoal pencil around the borders and at the center line for each section.
I think this kind of “shading” worked pretty well on the black. I will continue experimenting with it!
Zentangle drawn on black Strathmore Bristol using a white, Sakura gel pen. Shading done with Copic markers and black charcoal pencil.