Soft robots are more flexible than traditional machines and have the potential to squeeze into and explore more places. However, most of them need electronic components like circuit boards, valves and pumps to work. Those components are typically heavy, expensive and have to be tethered to the machines outside their body. Now, engineers from the University of California San Diego have developed a four-legged soft robot that doesn't need any of those to work -- in fact, the robot doesn't need any electronic component at all. Their soft robot has an onboard system of pneumatic circuits, which are made up of tubes and soft valves.