Spiral Jetty's strange markings deliberately reference prehistoric architecture - as well as American, Indian petroglyphs found in Utah, early spirals are found in many places in the Americas.
And on the wall, a cliff that they were working on this fine-grained basalt, there are actually petroglyphs, anthropomorphic petroglyphs that I think maybe are marking ownership.
I've studied other petroglyph sites, for example, on the island of Maui, where I did a lot of work, and the dryland side of the island area called Kahikinui.