Tiny, knotted robots jump, fly and plant seeds

When a knot lets go, it doesn't just fall apart. It snaps. That simple observation led Penn Engineers to rethink what a knot can do. Instead of treating it as something that holds tension, they asked a different question: what happens when you design a knot to release it? The answer is a tiny, soft robot capable of leaping meters into the air, flipping mid-flight, spinning like a propeller or even gliding back to where it started.