What patents do people think I can think of?

In the math class of grade three, I was thinking about how to make a lot of money without working. A good idea suddenly occurred to me, that is, borrow five dollars from one person, ten dollars from another person, and then pay back five dollars to the first person, so that I have five dollars to spend. As long as I keep borrowing money, I can have endless money. I was so happy that I stayed up all night thinking about my plan. Later, I learned that this thing is called Ponzi scheme, 100 years ago. I feel so sad.