I recently picked up a copy of Doug Chiang's Mechanika. I haven't done much with markers since undergrad, so I thought it was a good opportunity to flex the atrophied marker muscles and try some simple sketches.
Nothing too fancy, but the technique in the book was simple and really clean so I think I'll keep practicing. I miss drawing on paper. All I used above were prisma color markers, micron pen and a ruler.
A friend of mine asked me to help him design a Cthulhu themed sleeve tattoo, so I've been doing some reference research. I saw some interesting designs of morbid looking trees, and so I pumped out a little doodle that I ended up kind of liking: