"Two is a very interesting number."
"The Taoists say, 'Taiji gives birth to the two principles, the two principles give birth to the four symbols. The two principles are the initial form of the development of everything in the world. There is also the saying, 'the Tao gives birth to one, one gives birth to two, two gives birth to three, and three gives birth to everything.' Two is the transition stage of all things."
"Actually, the meanings are similar. Two is an important transition in the evolution of everything..."
Zhao Yi thinks hard and quickly shakes his head. He realizes that his thoughts are straying. What he studies is a mathematical problem, not Taoism, philosophy, and the like. "In mathematics, 2 is the only even prime number."
"The number 2 has always existed. Prime numbers are just a definition by mathematicians, but many rules and contents related to prime numbers indeed involve the number 2."