I've done a couple of Zentangle posies. I see that this first one has attracted a little red ink on one petal.
There are several free sources of Zentangle doodles. One is Suzanne McNeil's blog. She shows one per week, along with the step-outs of how to draw them. She usually incorporates one of the weekly tangles into a beautiful illustration.
Another is the Zentangle website.
A third is the Enthusiastic Artist blog.
Take a look at a few of these, and give Zentangle a try. It's kind of addictive!