The issue has always been who owns the property. There is a name for it but I am too tired to remember. A good movie/book adressing it is Ayn Rand's "The Fountainhead". The person who owns it can put any use limitations/restrictions they want. As someone suggested, best design your own or live with the restrictions. Essentially when you buy a design(emb. ) you can't change that much of it,claim it as your own or sell the design. This why they have copyright lawyers. Follow the money.