Folding liquid fiberglass bicycles

[Dave Long]

> The problem with stability is that you're standing on two points,
> rather than two whole feet, so without picking up one of them and
> moving it, there's no way to adjust your balance to keep from falling
> at right angles to the line between them.  Walking is already stable,
> but standing is like treading water.

Bilateral transfemoral amputees are sometimes started out on 
"stubbies", which have the feet attached just below the socket -- but 
in reverse, with the toes pointing backwards.  I believe the big 
attraction of stubbies is that the lower center of gravity makes it 
easier when learning a new set of ambulation skills, and the situation 
is probably reversed with powerisers, where one is not only higher up 
but can easily use knee action for break-over, but it does show that 
effective ground-contact solutions needn't be biomimetic.

-Dave