It is surprising that such things have not been created before. It's a few legs supported on a sideways axis. One would expect it would not have been hard to do

It is surprising that such things have not been created before. It's a few legs supported on a sideways axis. One would expect it would not have been hard to do it at least 50 years ago. But in robotics everything is about 1000x harder than one would naively assume, it seems. (Judging by how my vacuum robot with a friggin' laser scanner can't find its docking station from 1 meter away.)