d in those classes, and think about why the variables and methods were placed in one class or the other. For example, you may want to consider questions like the following: What does an object of type RobotWorld represent? What does an object of type Robot represent? The placement of walls and windows is handled by the methods addWall$()$ and addWindow$().$ Why are these methods placed in the Robot World class instead of the Robot class? The actual displaying and moving of robot icons is handled by the RobotWorld class, using methods like moveIcon$()$ and rotateIcon$().$ If these operations are performed by Robot World, why do the instance variables that store the robot's position and direction appear as part of the Robot class? The methods frontIsBlocked$()$ and rightIsBlocked$()$ are both part of the Robot class. However, these methods rely on the services of the method whatIsAt$(),$ which is part of the Robot World class. Could all three of these methods have been placed in one class $($either Robot or Robot World$)$