Ritual objects such as these were common grave goods and are found nowhere else. The symbolism is
debated with no consensus on details, but these sacred shapes probably represent different forms of heaven/earth unity. Master Chi, my Taoist teacher, told me this: "Through the 'empty' areas flows the infinity which dwells within the finite. This also is the passageway up through which the soul ascends." He also pointed out that seen from above, the Cong is a mandala form, the earliest known. The mandala in China (and in many religions) still symbolizes square "matter" and round "spirit" as the two fundamental aspects of our eternally combined reality. FLG