The nature of the publisher/maker system are basic in almost all computer games. As well as the purchase and takeovers by many companies. These are reasons why creative teams often lose to keep the copyright and trademark rights of what they made. This often makes attempts to make sequels for a product not possible for many reasons. One of the reasons it the "core" of the studio being fired or taken over after finishing a project while the parent company keeps control of the copyrights and trademarks. A good example of this strategy is Electronic Arts. They have closed many studios while keeping their copyrights and trademarks, such as Bullfrog Productions, Origin Systems, and Westwood Studios.