How do you decide when something is a violation of intellectual property? For example, if you tried to publish a book called “Sally Potter and the World of Bogwarts” about an English orphan girl who finds out she is a witch and goes off to a magic school, where she has lots of exciting adventures and learns to play quodditch, it would be considered an infringement on J.K. Rowling’s copyright on her Harry Potter books, even if you did not actually copy a single sentence out of those books. But at some point we have to take ideas from other books. Where do you draw the line?