How do I get these lines?

Hello all,

Grasshopper beginner here. Just a little exercise I did to get used to grasshopper but I'm bumping into a wall.

I'm trying to make a gherkin-like structure with this definition but the LineLine Intersect component isn't giving me the points I want, please help?

(I'm planning to connect these dots with Line component so they are straight lines)

Please see picture and the gh file.

Thanks a lot,

Ching