Nature digs up the info on the termite robots built this castle:
The robots all work independently. Each travels along a grid and can move, climb a step and lift and put down bricks. And they use sensors to detect other robots and existing bricks, and react to these stimuli according to a simple set of rules, such as when to lay a brick or climb a step higher. The template for each three-dimensional structure is translated into a specific set of ‘traffic rules’ and combined with fixed laws of robot behaviour, says co-author Justin Werfel, a computer scientist at Harvard University in Cambridge, Massachusetts.
Robots are useful in places that for humans would be “dirty, dangerous and dull”, says Werfel. This means that such swarms could be useful for the first construction project on Mars, or in the more immediate future, for building levees to protect against flooding. Independently acting robots make for a robust system, he adds. “If some got swept away by the flood, the others wouldn’t have to change what they’re doing.”