algorithmic modeling for Rhino
I've attached an approach that may simplify things a bit. I'm using "flip last matrix" from tree sloth, but it's just as easy to use the path mapper. The advantage to using flip last matrix is that the input data structure can change and you won't have to explicitly adjust it as you would the path mapper...essentially it identifies and uses the last path index that has multiple unique values.
I'm curious what method you used to group the points together initially...that really seems like the trickiest part of the definition!
thank you very much David interesting solution and indeed I used Trevor Patt script, but your curve network is TOO fast! many thanks again!