There's no shortage of proposed ideas for self-assembling robots, but they're usually either incredibly complex or just a little boring. In contrast, these adorable little cubes have no obvious moving parts—but can still climb over and around one another, leap through the air, or roll across the ground.
When you hit the gas pedal in a car, you get pressed backwards in the seat. That's physics. So why does a helium balloon dart forward, into the acceleration? Is helium immune to physics?