The middle son in the I Ching trigram family is the symbol of The Abysmal Water.
According to Wilhelm:
The Abysmal means water. It is the trigram of due north, the trigram of toil, to which all creatures are subject. . . He toils in the sign of the Abysmal. … The Abysmal acts in the pig. … of the domestic animals the pig is the one that lives in mud and water.
Painting inspired by the Chinese character for the Trigram Abysmal Water.
My original illustration for the trigram The Abysmal Water.