The word "fa" did not exist in ancient times, but only after liberation. It is a simplified word for "beard" and "bow". Although the pronunciation of "beard" and "bow" in ancient times is the same, they are two different words, which mean "beard" and "hair" respectively.
Rice grain and rice grain are variant characters, rice grain appears early and rice grain appears late. The calligraphy literature first seen by Wang Xizhi in the Jin Dynasty is a simplified word for rice in the Jin Dynasty.