One of the first things that attracted me to Zentangle and all the patterns is how patterns can be used to represent natural things like rocks, flowers, leaves, etc. and when I saw this week's Diva's Challenge, I was excited.
I have done several pieces that depict 'nature'. The one you see above was done a year ago.
And here is one from my Tangle Journal.
And here is one I did last night using Tagh, Jetties, B'tweed, and Featherfall. I have a difficult time using Festherfall, I think it's beautiful but just can not grasp how it's done.