I just re-read Robert Heinlein's short story "The Roads Must Roll" and there is a reference in the story to something like this, but he called it a tumblebug. F

I just re-read Robert Heinlein's short story "The Roads Must Roll" and there is a reference in the story to something like this, but he called it a tumblebug. From the story - "It had been a long time since the Chief Engineer had ridden one of these silly-looking little vehicles, and he felt awkward. A tumblebug does not give a man dignity, since it is about the size and shape of a kitchen stool, gyro-stabilized on a single wheel" I find it interesting that he predicted this in 1939 and it has taken 70 years to be a reality.