Your next house could be built by a swarm of quadrotors? It  doesn't seem so crazy after you have seen the video of them in action.

The autonomous quadrotor seems to be the flying robot of choice, but usually we just see them flying around looking menacing. Here we see a "team" of quadrotors flying in a cooperative effort to build selected structures. The actual construction isn't so complex because the beams snap together magnetically so the task is basically one of 3D positioning. As revealed in the video, however, the quadrotors have to work out the correct orientation of the beams to ensure that the magnetic connectors work. They appear to do this by detecting the difference between a "free waggle" and a waggle of the beam subject to a magnetic attraction.

Each of the quadrotors is autonomous and they are told the structure to build and they work out the assembly steps needed. It isn't  difficult to think of practical applications of such technology and while the idea of a team of quadrotors building your next house is perhaps a bit further into the future their use in hostile and emergency situations is obvious. But perhaps their main use at the moment is to spark the imagination. One of the comments to the video (knowsfords) make the point beautifully -

"You should totally get them to build hexagon shaped bays where they can store honey"

Yes indeed. The quadrotor seems to be the swarm component of choice.

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The work is by Quentin Lindsey, Daniel Mellinger, and Vijay Kumar at the GRASP Lab, University of Pennsylvania.