Is cursive script produced from official script?

Cursive script, an independent adult, was in the Han Dynasty, and its development can be divided into three stages: Cao Zhang, Jincao and Kuangcao. Cao Zhang was born in the Han Dynasty when official script prevailed. Horizontal painting and writing kept the tide of official script, which evolved from official script. In the Western Jin Dynasty, Cao Zhang's master had a land machine, and his masterpiece was Ping Fu Tie. Today's grass, also called grass, was developed and formed by regular script on the basis of Cao Zhang. The strokes of the upper and lower characters are connected, the radicals are borrowed from each other, and the strokes are continuous, which is the characteristic of their characters. It developed in Wei and Jin Dynasties and matured in the Eastern Jin Dynasty. Wang Xizhi's Seventeen Pieces and Wang Xianzhi's Duck Head Pill are handed down from generation to generation. Crazy grass, also known as big grass, began in the Tang Dynasty and is wilder than today's grass. His pen is ups and downs, continuous and in one go. Famous artists in the Tang Dynasty included Zhang Xu and Huai Su. The latter's self-narrative post is a typical work of weeds.