Connect Nth Item Of Each Branch

Hi all,

I'm new to the forums, but have been using Grasshopper experimentally for ~3 years. I have a simple question: How can I select/connect/group the Nth items of each branch in a data tree?

Specifically: I have a 100' vertical plane lofted between curved top and bottom profiles. I contour it every 8' (normal direction is Z, giving me 13 horizontal curves). I use Divide Curve to divide each contour into 10 segments. The "Points" output of Divide Curve now yields 13 branches with 11 items each, corresponding to 13 contours with 11 points from the left end of the curve to its right.

I now want to string "vertical" lines, and connect all the 2nd items in each branch together, all the 3rd items, etc... in order to make a polyline that travels between each 2nd point or 3rd point. i don't want to use Cull Pattern/Nth/Index because the number of subdivisions could change (11 could become 20, etc).

How do I connect the Nth item of each branch in this tree? Moreover, how do I connect all values in a branch with their corresponding values in all other branches?

Thanks for any replies,

Richman Neumann

Solomon Cordwell Buenz Architects