SRI International’s senior researcher Annioe Wong-Foy demonstrated a group of small robots working together to make structures bigger than them. Each individual robot is very simple and have only one or two metallic arms that allow it to make a set of predefined operations, but using several of this microrobots it’s possible to execute complex sets of operations, resulting in operations much more complex than those possible to each single robot.
At this point this is little more than a simple proof-of-concept, but it shows great potential.
More about this in MIT Technology Review, in Phys.org and in the SRI International website.