People have made stone spheres with primitive means already. See: https://en.wikipedia.org/wiki/Stone_spheres_of_Costa_Rica https://en.wikipedia.org/wiki/Sto

People have made stone spheres with primitive means already. See: https://en.wikipedia.org/wiki/Stone_spheres_of_Costa_Rica https://en.wikipedia.org/wiki/Stone_spheres_of_Costa_Rica