I do like contour lines, and this little doodle reminded me of wood cut through like when you cut down a tree. You can date the tree by its tree rings (dendrochronology) . I started out doodling round some pink and blue dots that had leaked through the page from a permanent marker pen, and then spread out and out, trying not to overlap the lines. This is like a meditation to me, as the pattern gets larger its more difficult to draw tidy curves and keep the line seperation. This took hours and i really had to concentrate. I’m sure it could be done with a digital platform but this is a fine liner ink pen.