John Payne from the Robots Podcast has sent news on a recent video by Daniel Mellinger and Vijay Kumar from UPenn's GRASP Lab. Following a great deal of other work with robotic quadrotor aircraft, their latest video above shows a team of quadrotors cooperating on a construction project. For more information on similar work (including some more complex cooperation tasks with pieces of wood), have a look at a recent Robots Podcast interview with Kumar and Mellinger, at Mellinger's YouTube channel and at work done by my colleagues at the Flying Machine Arena (FMA on YouTube).