I started with a general sketch of a face. Then I grabbed an ultra fine Sharpie and started drawing triangle shapes in areas around the face. I just drew a few triangles at a time, and then I free-handed the the repeating lines inside each triangle. I found this whole process to be very relaxing. It's not a style of drawing that I'd really done before, but I really enjoyed doing it. So you may find me doing this type of drawing again in the future.