Copyright/patent infringement is a mine field of extraordinary complexity. Inspired by is great for hangar talk. But if it is close enough for you to raise the issue, I would suggest that you contact a patent attorney in your area. In my thirty years of legal practice, I have always referred such issues to patent attorneys; they are a special breed. For possibly a few hundred dollars they may be able to save you thousands if litigation is initiated. There is a tremendous amount of litigation in this area of the law. A consultation would provide either peace of mind or a reason to do something different.