Stanford robotics prof. Allison Okamura reveals how her team built a robot that grows like a vine and could navigate the human body without the friction of traditional catheters: "A plant that’s a vine has this growth habit, the tip can keep moving forward. Take a tube of soft material, imagine Ziploc bag plastic, flexible but airtight." "Stuff it inside of itself, invert it, pressurize it, and it will grow and release material out of the tip. We’ve grown these things the length of a football…