Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences have developed a method for 3D-printing artificial muscle-like filaments whose movement is effectively programmed directly into the material.

Their work seems to be the closest to human-like muscles that robot muscle systems have gotten. Before we continue, you don't have to worry about competing for gym space during the robot uprising. It's not that type of muscle … yet. Now that we've gotten that out of the way, why bother giving robot muscles in the first place?

The thing is, the natural world requires flexibility. Everything from trees to octopuses bends and twists. We've also built a human world that demands this same adaptability. Infrastructures, clothing, tools, and even social interaction were all designed around the mechanics of soft biological bodies.