if i understand you correctly
it is rare but not really unique
another one occurs in baarle & a third in bengal
we have been calling these border crosses
there are many on lower than international levels too
the bwnazmzw quadripoint probability you mention is indeed different
& only exists sometimes
maybe
as it involves moving thalwegs etc
--- In
BoundaryPoint@yahoogroups.com, "Wolfgang Schaub"
<Wolfgang.Schaub@c...> wrote:
> All of you sure know the Jungholz enclave, surrounded by Germany
and bound
> to Austria via a quadripoint on top of Sorgschrofen. This is unique
in that
> it is the only one (? or another one at
Namibia/Sambia/Botswana...?) in this
> world where borders of independent countries meet.
>
> There is another uniqueness: Borders of just TWO countries form this
> quadripoint. This is only possible in a spiro binding, one border
across the
> other.
>
> Has anybody seen another spiro quadripoint in this world? The
Sastavci
> enclave in Bosnia appears to almost fulfill the criteria, but only
almost.
>
> Wolfgang