For our first assignment in Nature of Code we are asked to find an example of real-world “natural” motion and develop a set of rules for moving simple square using these rules.  I choose a “bird of prey” (http://en.wikipedia.org/wiki/Bird_of_prey).  Here is a video example of theses creatures in action:

and my example of their rules applied to a box:
http://ganucheau.com/processing/birdDive/

Next we were asked to add design to both the creature and its environment, as shown here:
http://ganucheau.com/processing/birdDive_Images/.