Question on appropriate etiquette. I have an idea for a Marked deck which is based on the principle of two popular marked decks (meaning the information the marks are showing). However, it would be with a completely different back design, marks and marking system, and would only use portions of the two decks I am taking inspiration from. What's the correct way to go about creating this. Do I reach out to the creators of the two decks and ask permission? Do I credit them and move on? I don't want to make anyone angry and more so break any infringement etc.