One year in Haikou. What changes have taken place in the direction and length of the midday sun shadow?

Haikou is located at 20 degrees north latitude, between the Tropic of Cancer and the Tropic of Capricorn, with direct sunlight.

Changes in the direction of the sun's shadow at noon;

When the direct point of the sun is between 23.5 s and 20 n, the sun is in the south and the shadow is in the north, and the shadow is the longest when the direct point of the sun is 23.5 s;

When the direct point of the sun is located at 20 N, direct light appears, the sun is overhead, and the shadow is the shortest, showing a point shape;

When the direct point of the sun is between 20 N and 23.5 N, the sun is in the north and the shadow is in the south.