When is a Product/Idea/Creation a true plagiarism of an original and when is it a mere copy?
Plagiarism is taking advantage of the effort of a third party that results in the creation of a crude or servile copy. However, not every copy has to fall under the sphere of illegality, because essentially inspiration is free and it is supported by the law and the reiterated jurisprudence that interprets it.
For there to be plagiarism, you must have the will to pass off someone else's work as your own, you must have that desire to be recognized as the author. That is, all plagiarism is a copy, but not all copy is plagiarism.
The expert evidence that is practiced and that will allow the court to conclude if we are talking about a mere coincidence, an inspiration or an unauthorized exploitation of the rights of a third party will be decisive.