1, there is little difference between cursive writing and running script writing. There are two main ways to write it. One is that the wooden characters above are written vertically first, and then horizontally and vertically, and the following characters are easy to write, such as the wise man's writing here. The second way of writing is to simplify the wooden characters above into two points on the left and right, and keep the rest unchanged, such as Li written by Huai Su below.
In addition, by the way, we usually see a more vulgar way of writing, especially in the signature of a friend surnamed Li, which is to omit the word below the word Li and add a little to the right. Although everyone knows what this word is, this kind of writing has never appeared in ancient calligraphy works. So I suggest you use it less. There are rules to follow in the changes of strokes, such as the urgent chapter of the Three Kingdoms Wu in Songjiang Edition.
3. It came from the Eastern Jin Dynasty to distinguish it from the new cursive script at that time. The cursive script of the Han Dynasty was called Cao Zhang. The new cursive script is relatively called today's grass, which is divided into big grass, also called crazy grass and small grass. It feels beautiful in madness. As Li Zhimin said, you should be in the pool, consider the reasons, learn from things, gain the heart, realize the image, and then enter the cursive wonderland. Because cursive script is too simple and easy to be confused with each other, it can't replace official script, and it becomes the main font just like official script replaces seal script.