The Robot Swarm
A kilobot is a modular robot about the size of a quarter. It can't do much on its own, but a collective of several hundred kilobots can work together to form shapes and overcome obstacles in their path.
Together, the robots act like a swarm, maintaining set distances from one other, communicating with neighbors, and coming to collective agreement about the position of each member of the collective.
In their article, "Kilobot: A Robotic Module for Demonstrating Behaviors in a Large Scale (210 Units) Collective", Michael Rubenstein, a post-doctoral fellow in computer science, and Radhika Nagpal, Thomas D. Cabot Associate Professor of Computer Science, demonstrate how a collective of robots can self-assemble into a desired shape, reforming the shape if it is disrupted or if there is a change in the number of bots.