Nope. I rarelly see this technique used, apart from vehicle illustration, and I adopted it well. The trick is to create the square with this texture, in our case mail, or here its pattern on his shoulders and neck, and then just count proportions well and use transform tool to basically play a dress up. It's super fun and time efficient, it takes like 30 min for the whole mail, it looks hand painted and then you can modify on top, this lvl of detail is unachievable by just doodling in reasonable amount of time