I have recently discovered the joys of TED. If you do not know the site, do yourself a favour and watch some of the articles.
Here is a video involving ‘flying quadrotors, small, agile robots that swarm, sense each other, and form ad hoc teams — for construction, surveying disasters and far more.’
Boadicea's Chariot 
Thanks for the hat-tip, Sipu. What a great site for geeks like me!
I’ve been looking at TED for a while – it is indeed an excellent site 😀
Sipu -Thanks for highlighting this site.
OZ