What bed did the ancients sleep in?

In China, the development of beds has a long history, and books record that beds originated in Shang Dynasty. There is also a legend that the ancient Shennong invented the bed. During the clan commune, people's living standards were very low. When they sleep, they just spread some hay and skins. After mastering certain weaving techniques, they spread a straw mat on the hay. After that, the embryonic form of the bed slowly appeared. The pictographic word "bed" appeared in the writings of Shang Dynasty. The earliest physical bed in China was found in a Chu tomb in Xinyang, with a height of 19 cm, six feet, railings around it and exquisite patterns carved. The appearance of bed gradually changed the tradition of ancient people sitting on the floor. But it was not until the Tang Dynasty that the bed had multiple functions. There were several tables on the bed, and sleeping, writing, reading and eating were all on the bed. After the appearance of tables and chairs in the Tang Dynasty, this kind of situation of one bed was gradually changed, and the bed gradually became the special furniture for sleeping. There are four basic forms of beds in ancient China: couch, arhat bed, rack bed and treadmill. Rack beds and treadmills are only used for sleeping, while arhat beds and couches are also used for receiving guests. From the Han Dynasty to the Ming and Qing Dynasties, receiving guests on tatami or arhat beds became the reception etiquette of the upper class. Generally speaking, the most commonly used bed in ancient China was a crib, with four or six columns and fences on three sides, leaving only the main entrance and the main entrance, which was complicated in decoration.