Boston Computer Museum designed to enhance public awareness and understanding of complex decentralized systems and emergent behavior. The exhibit was designed and developed at Nearlife Inc. in collaboration with the MIT Media Lab and the Computer Museum. To provide an engaging and entertaining view of how individuals can follow simple rules that lead to emergent group behavior, the exhibit focuses on the schooling behavior of simulated fish. Environment The overall feel is of being submerged at the bottom of a virtual undersea world inhabited by giant versions of kitschy fish tank objects. There are the obligatory diver, treasure chest, clam, and sunken ship. There are five different kinds of fish (two types are predatory), whose styles are inspired from actual fish but are more cartoony and robotic to highlight the fact that they are simulated. The fish swim freely between twelve 1024 x 768 rear-projected screens spanning a region of over 400 square feet with almost 10 million pixels. Recent advancements in processor and graphics accelerator speed allow the entire exhibit to run on 21 home PCs. Architectural details and interactives that cross between the real world and the fish tank world create a sense of illusion that visitors are actually in an undersea world. A wheel is connected to a pipe that goes into the wall. The pipe continues into the virtual space to an opening where virtual food pellets are released. When a visitor turns the wheel, food is released, and the fish respond if they are hungry. The fish can also react directly to visitors by means of a digital camera that detects motion using simple vision techniques. The user interface elements were designed to highlight the system of rules that governs the behavior of each fish. At four touch screens, visitors change the parameters of the fish rules, such as the strength of attraction or direction matching, and then watch the schooling patterns that emerge as each fish responds. At three more touch screens, visitors build and test their own fish in a miniature tank and then release it into the big tank. As visitors change the fish's rules, its appearance also changes. For example, making a fish very hungry will give it a large and fierce mouth. System Architecture The fish tank software is written on top of Nearlife's Directable Character architecture, which allows real-time, interactive, net-worked, autonomous character behaviors and extends the work of …