Sometimes, we need to create an exact copy of an object. For instance, assume that you want to create an application for storing, sharing, and editing presentation and marketing content for products promoted by a group of salespeople. Think of the popular distribution model called direct selling or network marketing, the home-based activity where individuals partner with a company to distribute products within their social network, using promotional tools (brochures, PowerPoint presentations, videos, and so on).
Let's say a user, Bob, leads a team of distributors within a network marketing organization. They use a presentation video on a daily basis to introduce the product to their prospects. At some point, Bob gets his friend, Alice, to join him and she also uses the same video (one of the governing principles is to follow the system or, as they say...
