Interesting that he pivoted to something more akin to a human in the later versions. And I feel akin is an interesting word here. Kin selection is well-studied aspect of how genes work at population scale; and I wonder if by just having human-like traits like in the direction your knees bend, helps make robots more agreeable to us. And the UX of full submission as a human approaches, however the optics, seems to be a pretty strong way to indicate to the human user of a non-threatening environment in their control. I should be able to clearly see if something isn't as it should be if the humanoid fails to do this upon approach and take precautions.