江恩说
This is the same rule that applies to a gravity center in anything.If we could bore a hold thru the earth and then drop a ball, momentum wuold carry it beyond the gravity center, but wen it slowed down, it would finally settle on the exact center. 这就是各种半点的重要性。同样。1x1线也是一个质心。每个质心代表一组特殊的波动率。