passing through a geometrical center: see Geometry.
emphasizing symmetry: a symbol of the desire for equality, i.e. a symbol unifying antitheses.
the rotation of objects around one's axis: represents time, fate and karma*26.
being part of the rotation around an axis: depicts constantly changing life conditions that make one dizzy; only through the gradual unification of antitheses that life contains can we get close to the axis of the rotation where the world no longer turns madly, and in the very center of the axis we find stillness, tranquility, peace and then even knowledge and liberation.