Nanoscopic DNA pyramids that change shape when sent different chemical signals, have been demonstrated by researchers in the UK and Germany. Such structures could act as the motors of nanoscale robots, they say.Other researchers have previously built DNA devices capable of walking along proteins or functioning like nanoscopic robot arms, but precise control of these 3D structures has proven difficult. Now Andrew Turberfield of Oxford University in the UK, and colleagues at the University of Bielefeld in Germany, have shown how carefully crafted DNA structures can be made to self assemble and change shape when sent specific DNA signals.