The eldest son in the I Ching family is the symbol for the Arousing Thunder.
According to Wilhelm:
The Arousing, whose image is thunder, symbolized by the dragon, which, rising out of the depths, soars up to the story sky—in correspondence with the single strong line pushing upward below the two yielding lines.
Painting inspired by the Chinese character for the Arousing Thunder.
My original image to depict the Arousing Thunder.