Hugh Newman investigates the geometric stone spheres found in Northeast Scotland, Orkney and parts of Britain and Ireland. What were they used for? How did they carve them? One was even found in Bolivia! Read Hugh's two-part article here: https://bit.ly/2H9YxU4.
This has some interesting basic facts and discussion, but it also suggests some complete bunk science and ideas like “energies” and “healing” which are far less likely. I’m not sure I can get behind any of the mathematical ideas.