In the world of mathematics, there is a famous adage: "Read Euler, he is the master of us all." Leonhard Euler was not only the king of productivity but also the "universal plugin" of the scientific world. Statistics show that Euler produced about 800 books and papers; remarkably, nearly half of this work was completed during the last 17 years of his life, despite his total blindness. Even more astounding is his ubiquity: his name is attached to hundreds of laws, formulas, constants, and concepts across mechanics, fluid dynamics, optics, and astronomy. If Newton laid the foundation of physics, Euler was the one who wrote its "universal language." It is often joked that the mathematical community has to add the prefix "Euler" to so many discoveries that it has become an inevitable standard.