A cross-section of wall paints from an 18th century theater. Each band represents a different coat of paint that was visualized with reflected light microscopy at 100-times magnification.
Image by Natasha Loeblich, Colonial Williamsburg Foundation.
So, just to recap, THIS IS PAINT.
This is what I think my wall sedimentary layers in the new apt look like (I am hanging things using the picture rail instead of nails in the wall).