I contended that the 'Inca Walls' with perfect cuts are actually geopolymer. I am not sure if I came up with this idea (first) with regards to the stones in Peru. The reason they are obviously geopolymer is that one cannot even get straight cut stones to fit together (in the modern world) as well as these 'curved cut' stones seem to fit together! Came up with the idea that they were all poured into biodegradeable bags, flattened against each other into a kind of mould and then this became the inca wall. Have had some support for this notion.