Shi Yang met Cheng Yi in Luoyang. Although he is forty years old, he still wants to study, so he went to see Cheng Yi. When he saw him, he was sitting dozing off. So Shi Yang and accompanying Youzuo stood there all the time. When Cheng Yi woke up, the snow outside was already a foot thick!

In the past, this meant that students received a respected education. Now it is a metaphor for respecting teachers, eager to learn and respecting learned elders.