Dublicate lines

Grasshopper
1

I have two groups of lines. One containing all my lines and one containing the lines I want to be removed from the first group. At the end I want only the diagonal lines to remain.
dublicate lines.gh (1.5 MB)

2

Like this?

Canvas at 23;05;00
Canvas at 23;05;00.png1458×522 484 KB
dublicate lines_re.gh (1.5 MB)

3

Almost. The long diagonal lines must also be removed.