If you worry about the domestic use of drones, this video may give you nightmares.

The nano quadrotors flying in formation. (YouTube)

Since at least 2010, researchers at GRASP Lab at the University of Pennsylvania have been working with nano quadrotors, managing to get them to fly aggressively, build a tower structure and now — fly in perfect formation.

The video posted by GRASP makes it clear the robots now know how to maintain distance from each other, shift positions when obstacles are in their way, and even fly in a figure-eight pattern. CNET reports that the research is a step toward coordinating robots for searching areas after a disaster, or for surveillance. Watch the video below: