I was plagiarized. Is there no patent to sue?

This situation is very difficult. Among intellectual property rights, only copyright is automatically generated, and trademarks and patents are generated after registration and authorization. Since you haven't applied for a patent for appearance or utility model, you don't have the patent right for pens and knives, and you can't sue with the patent right. Copyright protection is only a very concrete work and does not extend to technology and concepts. I don't know to what extent the other party copied the style you said here. If it is obvious plagiarism, you can still sue with copyright.