Inspired by some Pinterest pins, The Wifester and I decided on a Cleveland skyline for the brick wall that lines the back of our yard. We looked up many variations on the "recipe" for achieving moss graffiti, and settled on the one that called for 2 cups buttermilk, 2 cups water, and 2 tbsp sugar. You can use corn syrup to thicken, or corn starch (which is what we used). All of this thrown into a blender until thick and pasty, then brushed on the wall with a regular paint brush. The Wifester sketched out the skyline for us.
I'm hopeful that it will grow in nicely, and quickly. I will post pics every week or so to keep updated on the progress. Meanwhile, if you have a moment, please send my wall some good growing juju! Thanks!