Since I've pretty much had my head buried in the sand in regard to tangle-related stuff, I missed seeing the tangle pattern Narwal by Sam Taylor. I heard about it on Donald's blog and once I checked it out, of course I had to have a play. The pattern reminds me of a twisted rope using stacked "s" strokes - I've done drawings using this technique before - you can see one in this post - so I went with a similar approach to keep it more freeform and didn't use the pencil guidelines at the beginning which allows the pattern to go where you want it to.
First attempt - it's definitely a fun one to shade.
Next one......getting a little more interesting.
No. 3 - shades of green (with a little blue and yellow thrown in) - I'm generally not a big colour person, but I actually love this design with it.
If you want to see my approach, here's a quick video of me drawing the first example.