Height: 70cm; width: 28cm; thickness: 20cm; about 5000 years ago.
Humankind practiced group marriages and incest for some million years in aboriginal society. The earliest group marriages and incest occurred between parents and children as well as brothers and sisters, due to poor social advancements of the time. A single person or even a few persons were not strong enough to withstand natural disasters and attacks from wild animals. Thus, tens of men and women had to live in a cave together. Under such circumstances, incest became inevitable.
Eventually, the offspring of close relatives were born abnormal and retarded. Gradually they came to understand that reproduction between close relatives would affect future generations’ health. Because of this, there was conflict when looking for mates. For the sake of peace and unity, people began to restrict sexual intercourse. After the establishment of clans, marriages within a clan gradually changed into marriages between people in different clans. Sexual intercourse between a man and a woman became forbidden within a clan because they were closely related. Only those men and women from different clans were allowed to have sex. Every member of a clan, male and female, was tattooed with the same clan totem. They were required to have sex with only those men and women with different totems.