I went through a phase starting around June 2013 that lasted until around September. I did a lot of these Zentangle Inspired Art. I would draw something I saw online and then put patterns inside the negative space. I enjoyed this phase quite a bit and learned a lot about how I liked to shade. I really wish the scans of the drawings would show the shading at true value, but it's very muted compared to real life.
A lot of the images I would use would be some clip art or photo I found online and I would redraw it and tweak it to something I liked better and then add some patterns. It was nothing I could claim as original so I was still trying to find my niche in the Tangle world.
I still love creating this type of artwork. It's fun and a great way to try new patterns without having to think about where to put the next pattern because the lines are already on the page.
These are not the only ZIA I've done. It's a fun, quick release of creative energy for me. These five are the ones I did consecutively (or close to it) on my channel as I was going through that phase. I really recommend trying this out. Even if you can't draw, you can trace the images and fill it in with patterns.
Here's some videos: