I think this phenomenon is very difficult. I can only say that the calligraphy written by this calligrapher may change in stages, but the overall style will not change much.
Just like we said Yan Zhenqing's calligraphy. Yan Zhenqing's calligraphy in his life can be divided into three stages: small face, middle face and old face. Yan Zhenqing's calligraphy styles in these three stages are internally consistent, that is to say, his calligraphy is masculine, majestic and beautiful.
But there are subtle differences between each stage. For example, in Xiaoyan's era, Yan Zhenqing's calligraphy was more immature, and his identity had not yet formed a fully mature style.
But basically, the momentum is already there, and it is still in the stage of inheritance, and the writing is quite satisfactory.
During Zhongyan period, Yan Zhenqing's calligraphy style became more and more mature, his brushwork was bold and bright, his face was completely new, and he made many innovations in calligraphy.
Yan Zhenqing, in the old Yan era, has always been "doing whatever he wants without overstepping the bounds". The style is famous for being old and vigorous, and the style is completely mature. The representative work of regular script calligraphy, Biography of Magu Xiantan, is one of them.
Therefore, a calligrapher's calligraphy style can only present such a linear development logic, taking a continuous and tortuous route, and will not diverge, let alone breed two styles in the same historical stage.
As we said, a normal person can only have a personality system and a spiritual core, otherwise a person who is divided into two or three is not a normal person.
So do artists. We can only be a role, a contradictory body with various complex characteristics. But it will never divide unless it is pathological. Many times, in order to break through the limitations of self-development and self-breakthrough, many artists will force themselves and often embark on the road of division, which is probably the reason why many artists have mental problems.
Family nonsense, come and listen.