《文心雕龙·定势》
作者所模拟的范文，各有师承，虽然相互没有严格界限，却很难越过。
熔范所拟，各有司匠，虽无严郛，难得逾越。
The example essays that authors imitate each have their own teachers, and although there are no strict boundaries between them, it is difficult to cross them.