Answer the following questions based on what you read in Chapter 7.

1. Describe three principles of direct manipulation.
2. Give four benefits of direct manipulation. Also, list four problems of direct manipulation.
3. Examining the success of video games can provide insight for interface designers. Explain what lessons can be learned by video games for interface design, but also provide examples of areas where it is ineffective to do so.
4. An airline company is designing a new online reservation system. They want to add some direct-manipulation features. For example, they would like customers to click a map to specify the departure cities and the destinations, and to click on the calendar to indicate their schedules. From your point of view, list four benefits and four problems of the new idea compared with their old system, which required the customer to do the job by typing.