When dealing with gray areas in intellectual property law, you need to be very careful to ensure that you do not infringe copyright. Here are some suggestions to help you sell your adaptation without infringing copyright: 1. **Understand what is protected by copyright**: First, you need to clearly understand what is protected by copyright in the work in question, including text, visual elements, music, etc. Only new and original forms of expression are protected, while ideas, concepts and facts themselves are not protected. 2. **Use public domain works**: Works in the public domain are not protected by copyright and can be used freely. These works are usually works whose copyright has expired. Therefore, confirming whether a work is in the public domain is a viable way. 3. **Obtain permission**: Obtain permission to use their work by negotiating with the copyright holder, which can be through paying royalties or reaching some other form of agreement. 4. **Fair Use**: In some jurisdictions, the fair use doctrine allows the use of copyrighted works under certain conditions, such as for commentary, news reporting, education or research. Make sure to evaluate whether your use meets the fair use criteria. 5. **Create an original adaptation**: Make sure your adaptation is sufficiently different from the original work to demonstrate unique creativity and originality. This may include changing story elements, character traits, or incorporating other original content. 6. **Conduct a trademark search**: In addition to copyright, make sure that no trademarks are violated. For example, check whether your product name, logo, or other elements conflict with existing trademarks. 7. **Consult a professional attorney**: When planning complex or risky projects, it is best to consult an intellectual property attorney for professional advice and ensure that all steps comply with legal requirements. 8. **Create original content**: Try to create content from scratch. Although this requires additional effort and resources, it can ensure that the content is not subject to the copyright of others. By being careful and doing in-depth research, you can respect the intellectual property of others while protecting your own interests.