I just saw this article about a skyscraper stabilizing ball: http://deputy-dog.com/2008/06/22/in-action-a-skyscrapers-amazing-728-ton-stabilising-ball/ Why does that work? It's a swinging ball which also has some sort of supports underneath it. Are the supports just there to keep the ball from swinging too far? I tried to imagine that this was similar to holding a mace over my head and swaying the mace handle back and forth. But I can't picture it. Why would the mace ball stabilize my hand when held straight up? I just can't picture why this works. I saw the animation on that page, but I just don't see why that swinging motion helps to stabilize the skyscraper. Even if it somehow pulls it back, once it starts swinging wouldn't it reinforce the tilt of the skyscraper?