In the Song Dynasty, there was a man named Huang Bosi who was very knowledgeable about geometric figures. He was very hospitable and invented a "banquet table" composed of 6 small tables - a small table for entertaining guests. Later, someone improved it into a banquet table consisting of 7 tables. The tables can be assembled into different shapes according to the number of people eating, such as 3 people forming a triangle, 4 people forming a square, 6 people forming a hexagon... …This makes dining convenient for everyone and creating a better atmosphere. Later, some people reduced the banquet table to only seven boards, used it to puzzle, and evolved into a toy. Because it is very clever and fun, people call it "tangram". At the end of the Ming Dynasty and the beginning of the Qing Dynasty, people in the palace often used it to celebrate festivals and entertainment, and formed various auspicious patterns and words. The Palace Museum still preserves the jigsaw puzzle from that time! In the 18th century, the jigsaw puzzle spread abroad and immediately aroused great interest. Some foreigners played it all night long and called it "Tangtu", which means "jigsaw puzzle from China".