recently, a college student Wang Yong was in love with a girl in the library. He decided to write love letters to express love, and hid his love letter in a two-dimensional code. But somehow, this love letter appeared on the ground of the school. It was not until I met some enthusiastic student that I could see the love letter again. The enthusiastic student attached the two-dimensional code love letter to the door of the library, and added a title "Wang Yong, your love letter dropped". In this way, Wang Yong, who wants to express himself in a low profile, has an unexpected fire.