Problem
1. Select some graphics application with which you are familiar and set up a user model that will serve as the basis for the design of a user interface 101 graphics applications in that area.
2. List possible help facilities that can be provided in a user interface and discuss which types of help would be appropriate for different levels of users.
3. Summarize the possible ways of handling backup and errors. State which approaches are more suitable the beginner and which are better suited to the experienced user.