Stair Sweeping robot in action.

We first populate the world by reading a file with the wall and beeper specifications. We show that a beeper knows how many beepers are on a corner. Then we drop a StairSweeper robot into the world (shift-click). It is automatically placed in the correct position by its constructor.

We inspect the robot to see that it has no beepers initially. We then run the simulation and see the robot climb the stairs and pick the beepers. Inspection shows that the robot now has three beepers.

Next, we Reset the world and run another short simulation, which is part of the newspaper retrieval task from Chapter 2 of the book (before classes and methods have been introduced). Finally, we show the code of that task by double clicking on the ManyTasks class icon in which students may build their Chapter 2 solutions.