The robots glide across the floor, sometimes pausing to spin a quarter turn or two before resuming their route. They come close to one another but never collide. It's not choreographed – they're adapting on the fly – but the movement does have the feel of a ballet. If ballet dancers were mechanized platforms on wheels, that is. Flat-topped and low to the ground, like oversized bathroom scales granted the gift of movement and the ability to navigate on their own. These are Amazon's Proteus robots in action.  ...