Obviously, the first thing I was thinking about was the similarity of the two wheel/suspensions designs. Next up, I was wondering about the engineering decisions which resulted in the designs being similar. The main question I have is, "What advantages did the multi-wheel designs have?" I think it must have something to do with trade-offs between mobility on the (theoretical) terrain and power consumption, but really, I'm just guessing. Whatever the reasons are for the similarities, learning the engineering and testing behind the two designs would be fascinating.