Seasons of the year

The variations of the angle of the plane of the equator to the plane of the orbit of the earth around the sun causes seasons. (And these variations are due to axial tilt). At 22 Dec the plane of the equator (PE) is upper then the plane of orbit(PO). At longest angle. It starts decreasing afterwards. At 22 Mar they are in line. It starts to increase afterwards. At 22 Jun the PE is lower then the PO. At the longest angle. Now it decreases again and again becomes zero at 22 Sept. When the two planes line again.