Boids of a Feather Flock TogetherShawn Carlson explains how to simulate simple organisms on your computer Scientists sometimes struggle to understand why certain animals act as they do, especially social animals.A school of fish or a flock of birds, for example, behaves in many ways like a single creature. Yet exactly how the individuals organize themselves into a "superorganism” is still very much a mystery. But believe it or not ,these days insights into such self-organizing communities seem to come more often from computer hackers than from field biologists.Many programmers are creating on their desktops virtual environments populated with simulated animals.The nature of these artificial life-forms (or "a-life”, for short) usually hinges on a special data string,which is analogous to the DNA blueprint of a living organism. This digital code defines how an a-organism interacts with its cybersurroundings and determines the likelihood that the simulated creature will reproduce.