List of scenarios discussed in the book

Leaves and Wombats          (Chapter 1)

This is a simple example showing wombats moving around on screen, occasionally eating leaves. The scenario has no specific purpose other than illustrating some important object-oriented concepts and Greenfoot interactions.

Asteroids 1          (Chapter 1)

This is a simple version of a classic arcade game. You fly a spaceship through space and try to avoid being hit by asteroids. At this stage, we only use the scenario to make some small changes and illustrate how to edit source code to change program behavior.

Little Crab          (Chapters 2, 3, 4)

This is our first full development. Starting from almost nothing, we develop a simple game slowly, adding many things such as movement, keyboard control, sound, and many other elements of typical games.

Fat Cat          (Chapter 2)

This is a small scenario serving as a basis for exercises with methods calls and simple statements. Make the cat perform, while you practice your Java.

Stickman          (Chapter 3)

Another small exercise scenario. This does not do much to start with, and we use it to do some exercises with if-statements at the end of the chapter.

White Blood Cell (WBC)          (Chapter 5)

A typical side-scrolling game. We develop it from a very primitive, rudimentary start to a full, playable game. You steer a white blood cell through an artery to catch and neutralize bacteria.

Piano          (Chapter 6)

An on-screen piano that you can really play.

Bubbles          (Chapter 6)

A small scenario serving as a platform to practice writing some loops.

Autumn          (Chapter 7)

This scenario shows leaves floating in the air, occasionally blown around. It is not a game, or any completed project in any sense, but it gives a good first look at collision detection and lists.

Newton’s Law          (Chapter 8)

Newton’s Lab is a simulation of the motion of stars and planets in space. Gravity plays a central role here. We also make a variant of this that combines gravity with making music, ending up with musical output triggered by objects under gravitational movement.

Asteroids 2          (Chapter 9)

We come back to the asteroids example from Chapter 2. This time, we investigate more fully how to implement it and add some more game elements.

Loop Practice          (Chapter 9)

As the name suggests: a scenario with the sole purpose of reinforcing the use of loops. This scenario could also be used much earlier for similar exercises.

Greeps          (Interlude 2)

Alien creatures land on earth to collect tomatoes. This scenario is a competition: program the greeps so that they collect as many tomatoes in a limited time.

Color Chart          (Chapter 10)

A small scenario just to display a chart of RGB colors.

Smoke          (Chapter 10)

This scenario demonstrated a visual effect: smoke trailing a moving ball. In general, it serves to discuss dynamic drawing, to create more interesting visuals.

Path Follower         (Chapter 10)

A small scenario demonstrating a creature following a colored path on the ground. This example is used to practice more work with color.

Foxes and Rabbits          (Chapter 11)

A predator/prey simulation. This scenario is fairly complete, and we use it to make some experiments and gain some understanding about the nature of simulations.

Ants          (Chapter 11)

A simulation of ant colonies searching for food, communicating via drops of pheromones left on the ground.

Simple Camera          (Chapter 12)

Showing a camera image on screen, using the Microsoft Kinect.

Greenscreen          (Chapter 12)

Using Kinect input to create a greenscreen effect (placing a user in front of a fixed background image).

Stick Figure          (Chapter 12)

A demonstration of skeleton tracking with the Microsoft Kinect.

Body Paint          (Chapter 12)

We extend the skeleton tracking to allow multiple users to paint on screen by waving their hands in the air. Again, making use of the Microsoft Kinect.

Kinect Pong          (Chapter 12)

A very simple game, but this time with gesture input instead o keyboard control.

Fred With Radio          (Chapter 12)

A last demo scenario for the Microsoft Kinect. We do not discuss this scenario in the chapter, but it serves as a model demo for studying how a cartoon character could be controlled by gestures.

The following scenarios are presented in Chapter 13, and selected aspects of them briefly discussed. They are intended as inspiration for further projects.


A simulation of a marble board game. Marbles have to be cleared of the board within a limited number of moves. Contains simple physics.


A start of a lift simulation. Incomplete at this stage—can be used as a start of a project.


A demo showing flocking behavior: A flock of birds flies across the screen, aiming to stick together while avoiding obstacles.


A demo of a more sophisticated explosion effect.


This is the start of an implementation of the classic Breakout game. Very incomplete, but with an interesting visual effect.

Platform jumper

A demo of a partial implementation of an ever-popular genre of games: platform jumpers.


This scenario is a simple demonstration of a physical effect: the propagation of a wave on a string.


A scenario showing use of live data from the internet, in this case Google maps.

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