The world of robotics is certainly making a great deal of headway. We are seeing some amazing things happening.
Creating swarms is a pathway that is being followed in many fields. The idea is that robots can work together to accomplish a multitude of tasks.
In this instance, a team at Northwestern was able to get a swarm of robots to work together to form letters. The key aspect to this was that it took place without the algorithm telling them what to do.
Instead, the letter was chose and the robots "figured out" how to assemble them.
The fact that robots can come together in an assortment of shapes is part of the path to creating larger systems comprising of smaller units. The ultimate end game might be a shapeshifting robots similar to the T-1000 in The Terminator Films.
In the future, the applications could be incredible. Consider the idea that a building block for a house was a "robot". Thus, only the design of the house needs to be spelled out and the "robots" would determine how to arrange themselves in order to complete the structure.