Here’s a nano swarm in action...https://youtu.be/YQIMGV5vtd4
In 2002, I worked for a startup company which had Dan Golden, the ex-administrator of NASA on our board. He brought in a technology advisor who had final launch authority on the shuttle missions. They were discussing research they were involved with on swarms of UAVs and smaller drones. We were involved with DARPA programs at the time, although in a different area. At the time, heir discussions of drone swarm R&D and the future of micro-UAVs sounded just crazy.
Turns out this wasn't long after the 1997 launch of a DARPA multi-year, US$35 million development program to create "micro air vehicles (MAVs)". The MAV project's goals was to develop a microdrone whose largest dimension was no more than 6 inches; would carry a day-night imager; have an endurance of about two hours; and be very low cost. At the time, these were thought of as military weapons which would operate with a high degree of autonomy to be used in the squad-level combat environment. MAVs capable of hovering and vertical flight would be used to scout out buildings for urban combat and counter terrorist operations. A MAV could be included in a pilot's survival kit. A downed pilot could use it to keep track of enemy search parties, or as airborne radio relays to search and rescue units.
The phase-one DARPA study ended in 2001, and was followed by a phase-two study that focused on particular vendors with an intent to develop MAVs closer to operational specification. A number of different MAVs were developed as part of these DARPA efforts.
At the time, I didn't realize I was glimpsing the future.
Then, just ten years later, it was a reality in a university research setting (the video you posted). And only a few years later, at the 2018 Winter Olympics in South Korea, Intel was flying a swarm of 1,218 Intel drones doing "digital fireworks" displays.
From early concept to huge swarms in about 20 years. Amazing.