I am thinking of a design concepts for foot prosthetic, and I fathom that the elephant hind leg is suitable for an investigation.
It is perpendicular to the hip, which is what happens with amputations above knee, the prosthetic is perpendicular to the upper leg bone.
For the fleshy hind pad we could simply use a small rubber ball, tiny basketball would do.
This allows a person to walk for long distances, but unable to move fast, it is a slow gait and no gallop nor running feasible.
It is a scary horrible looking design but I suspect it could be worked into an efficient leg with least wear and tear.
I was thinking about this leg for the countries where the people have mostly dirt roads. The Western walker has nice time on the good roads, but in most other regions of the world dirt roads are what people trek though.
Also was thinking it is going to be much easier design to fabricate.