How a Flock of Drones Developed Collective Intelligence

The drones rise all at once, 30 strong, the domes of light on their undercarriages glowing 30 different hues--like luminescent candy sprinkles against the gray, dusky sky. Then they pause, suspended in the air. And after a couple seconds of hovering, they begin to move as one. They've decided to head east. The drones at the front approach a barrier, and their tummies turn teal as they veer south.