Site Iny-7 , Big Petroglyph Canyon, in the Coso Mountains of California is part of one of the most spectacular concentrations of rock art in North America. The petroglyphs are thought to relate to shaman pursuing vision quests, seeking the help of spirits to make rain. Panels such as this invite the question: was the power cumulative? Did a shaman engraving a Bighorn Sheep or a self-portrait over an older glyph gain more from the effort than choosing a fresh pane of varnished lava?