The article answered those questions: First, all the robots are put together in an unformed blob and are given an image of the desired shape to be built. Four

The article answered those questions: First, all the robots are put together in an unformed blob and are given an image of the desired shape to be built. Four specially programmed seed robots are then added to the edge of the group, marking the position and orientation of the shape. These seed robots emit a message that propagates to each robot in the blob and allows them to know how “far” away from the seed they are and their relative coordinates. Robots on the edge of the blob then follow the edge until they reach the desired location in the shape that is growing in successive layers from the seed. The algorithm had to account for unreliable robots that are pushed out of their desired location or block other robots performing their functions. Nagpal’s team overcame this challenge by implementing strategies that allowed robots to rely on their neighbours to cooperatively monitor for faults. They also avoided relying too heavily on exact positioning within the shape boundaries.