Many of the stone walls of Petra were rough uneven and unsightly. To make them look good the workers put heavy amounts of plaster on the walls and drew in the stone blocks to make the wall look neat. Some of the walls were so uneven that the plaster in places were almost a foot thick. Workmen still do that to some degree.
I had some work done on my house and noticed some big cracks between joints. I asked the workers about the cracks in the wall.
Their reply was, "That is why they make painters putty." Sure enough they filled the cracks with putty and painted over the error. Some things never change.