Combining pencils with erasers is a Japanese patent.

Apply for a patent with the State Patent Office. When you get the patent certificate, your invention belongs to you. Whether this patent can bring you money depends on its practicality. You said that Japanese people combine pencils and erasers, and it is precisely because they need such things in real life that Japanese people will become billionaires. If you invent something practical and solve many problems in your life and work, naturally someone will buy your patent. Then sit down and enjoy the success. It not only got money, but also benefited mankind. Why not?