There are many changes in fonts, but the only constant is composition.
No matter what style of calligraphy you write, its composition is the same.
Composition, here we temporarily put aside the broad definition of composition, narrow understanding is more popular.
For example, when we are writing, (let's take vertical writing as an example for the time being) we should have written vertically, but cursive or running scripts are mostly fluent and unrestrained, so it is not appropriate to write rigidly in vertical columns. If so, we should also write in vertical columns (not discussed here). Cursive or running script strokes are inevitably unrestrained, long and short, and will not be arranged vertically on the prescribed vertical line, resulting in the feeling of "writing bent". If the first column is bent, the second column is bent, which looks unsightly, and even most writers will choose to abandon it. If they understand the composition, the third column can be bent to the other side appropriately, and the fourth column can be bent again.
Then in the process of bending, in order to achieve the density relationship between words and lines, some words should be small, some words should be large, and some strokes should be long.
No matter how straight and curved, the whole length should be balanced and harmonious in the end. As shown in the figure below:
There are still many rules and regulations. What I understand is far from the true meaning of my vast China calligraphy art, but you and I communicate and share.