Apples Design Patent D661,296
Within the comments is the text:
We all borrow because it has all been done before and we are not the originators. To merely copy is to take an existing interpretation and not run away with it. To steal an idea is to take something of value and make it yours. To make an artistic element yours you have to interpret it your way with your own approach.This cannot be done when you are merely copying the idea. When copying the idea you are just doing everything exactly like it was previously done. When you have done it your way you have used the element and not simply duplicated it.