Interpolate between points

Hello,

So I'm having this issue where I can't get a line to pass through these points.  I had my definition set but my computer died and the definition was lost and no where to be found in my grasshopper autosave folder :(.  It is very simple but I can't figure it out since a friend showed me how to do it.  There are three surfaces one directly above the other with random points generated on each.  I want a line to pass through each of the points (1 to 1 to 1, 2 to 2 to 2, 3 to 3 to 3, etc) to get three lines. or however many points there are on the surface.  I want the line to pass through the point as a curve, not a perfectly straight line. I have attched my rhino and grasshopper definition showing the begining of the defintion and failed attempts. All help is appreciated.  Thank you

-N