Via Kurzweil AI, check out this New Scientist report on a new modular, shape-shifting robot:

A shape-shifting robot comprised of many independently moving components has been demonstrated walking, rolling and slithering for the first time.

The prototype robot - called ATRON - demonstrated its various metamorphoses in Tokyo on Wednesday. For example, reconfiguring its many individual modules allows the robot to change its mode of locomotion on command.

As you can see in the photo, the modules are described as being "roughly spherical" in shape. Here we have a primitive, macro-scale implementation of the modular nanobot. All we have to do now is make these robots a little smarter and a little more mobile (they need to be able to fly and swim as well as roll around on the ground) reduce their size by a factor of a few million, and figure out a way to start producing trillions of them. Then the fun really begins.