In October 2010, we visited a very isolated geoglyph way out in the Great Basin desert, all by itself, on a basalt hill. It was an interesting discovery for us. There are some other Native American camps in the area but no petroglyphs that I could find. But, besides the remoteness, what makes this interesting is the height of the rocks stacked to make the geoglyph. They are all good-sized basalt boulders, typically 9-12 inch in diameter, and stacked three or four tall. The rock circles that are part of the geoglyph seem like they could have been used for housing rings.
It is also possible that the geoglyph could be a large hunting blind. The lines of rocks would likely have been used to drive animals, like antelope, in parallel to the line and the rock circles used as blinds for the hunters. Regardless, it all seemed unusual to me.