A very promising field of nanomotor research are DNA nanomachines. These are synthetic DNA assemblies that switch between defined molecular shapes upon stimulation by external triggers. They can be controlled by a variety of methods that include pH changes and the addition of other molecular components, such as small molecule effectors, proteins and DNA strands. Researchers have now designed and built a simple DNA machine that is capable of continuous rotation with controlled speed and direction - a function that might be very useful for example for molecular transport. This machine is driven by an externally controlled electric field. When this field is oscillated between four directions, it continuously reorients a rotor DNA that is asymmetrically attached to a DNA axle.