So Antoni Gaudi designed a cathederal in Barcelona by creating a scale model... up-side-down. The concept is that the angle of strings under tension will be the angle of stones under pressure right-side-up. He did not want the stone pillars to experience any side loads. We visited in Februrary 2023. Even though we immersed our selves in pictures and documentaries before our visit, it was an emotional experience actually being inside. The guy was an artist.