This is one of my absolute favourites, called Scrolled Feather by Helen Williams. I love its soft and flowing shape and I find it an absolute pleasure to draw.
I was asked by some of my readers if 1) they could follow my lead and also make a rolodex based zentangle design library? Of course you can, I am sure I am not the first to do this and I will not be the last, so please go ahead and share the result with us ;)
And 2) if I draw the methods of construction for each design on the back of my rolos? Yes, I do. I keep it rather unspectacular since its only for my own reference, but I will post this one as an example for you ;)