Here is one of the postcards my parents have sent. It is from the Petrified Forest. The picture is of a petroglyph panel. Ancestral Puebloan People use the natural "desert varnish" as their canvas, chipping away the darkened surface to expose the lighter sandstone beneath. Here is what my parents wrote on the back: "We never stopped here when you kids begged us to so we're stopping now. Mom & Dad"