A prominent feature of a circle is that the distance from the center of the circle to all points on the circle is the same, that is to say, the distance from the bystander to the circle where the bystander is located is the same, thus achieving a balanced state. The distance between people and onlookers is the same, which has a sense of security and can achieve the same visual effect. . . Think about it, if people stand in a square, the people standing in the middle of the four sides (that is, the people closest to the center) can see more clearly, but because others stand farther away, it will cause some psychological imbalance. After all, there are so many people watching, but you may be hurt by the onlookers, so he will step back and find a balanced position. People at the same four points are farthest away and want to see more clearly, so they will lean in and eventually form a circle. . .