Symmetric structure, golden section structure and S structure. What are these?

These are all photographic terms. Symmetrical composition has the characteristics of balance, stability and echo. Disadvantages: dull, lack of change. It is often used to represent symmetrical objects, buildings and objects with special styles. The golden section composition, well-shaped composition (nine squares composition) and three-point composition we usually talk about are actually simplified versions of the golden section composition, which are more suitable for portrait photography. As long as the picture is divided into three equal parts with two horizontal lines, and then divided into three equal parts with two vertical lines, the picture is divided into nine equal parts, and four dividing lines appear four intersections. We can assign the subject to one-third of the area, or to four golden sections and four golden sections, and the picture will be established. S-shaped composition, the overall visual experience of the image in the composition is S-shaped, not the standard S-shaped. The aesthetic feeling in the picture has been fully exerted, which is first reflected in the aesthetic feeling of the curve. S-shaped composition has strong dynamic effect, which is both dynamic and stable. All kinds of pictures can be selected according to the subject matter. The best effect is to express the natural ups and downs of themes, such as mountains, rivers and regions. It can also show many curves of human body, animals, objects and various natural and artificial forms. Generally speaking, the S-shaped composition extends from the lower left corner to the upper right corner of the picture.