Anything has a margin, but their history will make you laugh.

It is not simply a comment of the teacher but the reasoning that the edges of the book are so interesting is really interesting!

When you were in school, you must have been used to borrowing a ruler and slapping a piece to "draw" the margin of your notebook.

But do you wonder why we are hacking?

The edges of the play we often see.

In fact, this section of the notebook is created to create space for teachers to note comments or remind students.

This is also to facilitate the "male and female" to add more information to the lesson when "missing".

Individual mice often choose notebooks and books to "sharpen their teeth" .

However, these hinges are actually more special than in the past. In the olden days, when the cabinets were still not very popular, the books and books were quite loose so they were "bait" for the mice.

Ancient people created empty space on the sides of the book to minimize the information carried away by mice, cockroaches and bugs.

Individual mice often choose notebooks and books to "sharpen their teeth" . So books, old notebooks are often tarnished at the corners. The streaks of the mouse accidentally bring information on paper.

So to avoid this, the ancients have figured out how to create empty space on both sides of the book, to minimize the information brought by mice, cockroaches and bugs.