You will be amazed that you can use these ordinary items in a different way

A red side margin

In many notebooks, you’ll see a red line drawn on the paper. This is also called the side margin, and it used to have a useful function. In the past, rodents always gnawed on paper. This was often on the sides. The red side margin showed where the rodents often gnawed, so you knew where to write.

Image: Unsplash, Aaron Burden