It's about what you define as "free standing" i.e. self supporting, which at least means no wire anchors, but arguably also means no pyramids because they are a

It's about what you define as "free standing" i.e. self supporting, which at least means no wire anchors, but arguably also means no pyramids because they are a sort of refined mound, no ziggurats, no cheating by excavating around mountains and putting a cap on it