Vinca plant in graphite - line study

This is a graphite pencil drawing of a Vinca plant that I did for a course in botanical illustration a few years ago. I thought I had uploaded it here before, but guess I had not. The piece was supposed to be done entirely with line work (employing thick/thin lines bold/faded to indicate depth when possible) basically showing what you could do *without* shading. Very interesting exercise. I hope to someday redraw parts of this in pen and ink, and then maybe get another plant and work on some light and shade studies.