about 35,000B.C. and ended about 10,000B.C.
the nomads who hunt and fish for a living like to carve dots, lines and symbols on walls, bones and ivory from ancient mammoths
Put together traces from all over the world, and found that the code is related to the change of day and night and the waxing and waning of the moon
historians have understood
These codes are not only a form of artistic expression, but also a form of writing close to ancient people and have a certain meaning
It seems that man was making a real efforts to understand the seasons 20,000 years earlier than has been supposed