mr-John, these two designs are similar in some ways but not at all identical. So, it’s not easy to define how much change is sufficient to treat a design as “one’s own”. Why get so tied up in this type of argument. If you create a design that you clearly know was stimulated by another designer then just say so and publish it as a CAD or hardcopy. If you create a design that you later find out looks very much like another designer’s work, just update it with the comment that it was independently created but does looked another person’s design. These are both common occurrences. We all just need to live with telling it as it is.