How do you program a robot that is made of DNA? With a trail of breadcrumbs, that’s how. Well, not exactly breadcrumbs; more like a track of single-stranded DNA molecules that tell the robot whether to walk, turn or stop. A team made up of researchers from Columbia University, Arizona State University, the University of Michigan and the California Institute of Technology reached a new milestone when they got their “spider” — a four-nanometer molecular robot — to walk 100 nanometers. Sure, that distance is literally microscopic, but it amounts to a full 50 steps, destroying the old record of just three.