Another explanation is that the geometric designs are depictions of entoptic phenomena or phosphenes that are seen during trance states. There is remarkable sim

Another explanation is that the geometric designs are depictions of entoptic phenomena or phosphenes that are seen during trance states. There is remarkable similarity in these designs between groups of ancient people separated by thousands of miles and years: e.g. Australian Aborigines and San in Africa. The Signs of All Times: Entoptic Phenomena in Upper Palaeolithic Art https://www.journals.uchicago.edu/doi/pdfplus/10.1086/203629 https://www.journals.uchicago.edu/doi/pdfplus/10.1086/203629 Entoptic Imagery and Altered States of Consciousness http://entheology.com/research/entoptic-imagery-and-altered-states-of-consciousness/ http://entheology.com/research/entoptic-imagery-and-altered-...