Debunking Moss Graffiti

Have you heard of moss graffiti or moss art? Outdoor walls and surfaces covered in mosses shaped into words or images (Google Images). Many articles on the internet promote mosses as an easy way to create living/green art. As a scientist who regularly grows mosses in the laboratory I have a number of issues with this art form, but let's start with methods.   There are two methods described Image may be NSFW.
Clik here to view.Image may be NSFW.
Clik here to view.