When thinking about Intellectual Property (Chapter 20), how many different types of intellectual property are listed in your textbook? Considering each type of intellectual property, name it (the type of intellectual property) and provide a brief description of what that type of intellectual property is or entails (provide a couple of features at the very least). For each one of these types of intellectual property, explain a difficulty or challenge (whether with respect to obtaining it, defining it, enforcing it, maintaining it, etc.).