Rules are compasses and rulers. All our architecture, surveying, mechanics and physics are inseparable from rules and regulations. From quantum to the universe, rules can be used to measure and calculate (second difference). Fuxi's Eight Diagrams (binary) evolved from Luo Shu (decimal). Music was invented by numbers, while Gong Shangjue and Zheng Yu (some people say that music was invented by Pythagoras) invented geometry by rules (this is Euclid's). But since entering the digital age. I found that big data can not only predict the weather, but also predict what you want to buy. Perhaps the original gossip is also a tool for mathematical calculation and prediction. We just forgot the algorithm (how to use it). I heard that abacus is also a calculation tool, but people who don't know the formula rarely use it.