In a short time I asked three questions about more or less about the same subject:
which surfaces have (for a large area) a constant negative curvature?
"Hyperboloid like surface" as hyperbolic plane / pseudosphere
and (on math overflow)
(each time getting different good answers, the subject is just rather confusing)
After some more studying I now know more about the subject (the subject is just larger and more confusing than I previously realised)
Now I think it is interesting for others who would like to know more about this confusing subject. (even some respected textbooks have I think misinterpretations)
Can I make a new question and answer it myself (with linking to the questions above ) or are there better ways to cleanup the mess I made?
Or would this just increase the confusing?