Do you know how I can make a nonclosed interpolated curve like in the image?
I moved this to the Grasshopper category. Because a Grasshopper network is shown in an illustration I assume the question is about using Grasshopper.
What is the input?
How were the curves in the illustrations created?
Upload your .gh and .3dm files if possible.
You have an error in the expression on the Size (S) input to the Partition List component.
You have the expression set to x - 1 if you change it to x + 1 you will get the result you want.