Senses
衔石填海/ 銜石填海 to show indomitable will
To show great determination and persistence in the face of daunting challenges, especially for revenge or to right a wrong; based on the legend of the 精卫 bird trying to fill the sea
衔石填海/ 銜石填海 to labor in vain
To carry stones in one's beak to fill the sea; to engage in a futile or impossible task