Generate surfaces between lines

Hi everyone,

I am trying to generate surfaces between a group of lines using ‘Loft’
But it seems like the operation only takes the first line and the final line and generates only one surface.
Attached grasshopper file: MSc project steel (12.2 KB)
Is there anything i can do to improve the situation?

Thank you

You are generating two surfaces, one using positive length lines and the other using negative length lines.

P.S. Please don’t start a new thread for every aspect of this simple exercise: