I hope you don't mean "Boids" and the three-four simple rules, because that's just an approximation of a swarm behavior made for artistic purposes - i.e. the result is supposed to pass as a flock of birds or a school of fish to casual onlookers (e.g. gamers, audience of a movie), and not to be accurate to the real thing.
'Robot Sheepdog' : https://www.youtube.com/watch?v=tefXVXscNDM
I'd like to add, that while individual behavior is difficult to predict, a general motion prediction can be much easier. (Think shepherds, for example)
The "swarm" is meaningless there. Each node need to have minimum amount of sensing and computation to handle that job.
It's also at worst "a sloped square" so there is no "swarm mechanic" to move around, just zigzag around the field.
But we had made it so much more complicated because we couldn’t see the few simple rules that each of them were following.
Honestly, I think robot swarms will be simpler than large singles.