The "plan"

I was looking at the photo of lichen from the stone wall on my site, and I noticed a certain pattern. The lichen was not as abstract as I first thought, upon further inspection. It is quite geometrical in fact, made of pentagons/octagons (roughly) layered on top of each other. I selected one portion of the photo:

This was what I thought was the central shape in the photo, thus the one I would focus on. I then isolated the main lines that went into this particular form:

One I had this, I doodled on photoshop how the design could look like:

Whilst I am using this as a basis, I intend my site to be longer (around 8m in length) than it is wide, so this design will require some altering, however I would like it to somehow retain it's roundish shape, as it is very reminiscent of a "growth" coming out of the architecture.