Problem organizing list

Hi,
I have two lists of geometries and im trying to find the intersection points between the two and then have one list that is organize in 8 branches which corresponds to each individual open curve of one of the lists, and inside each branch their intersection points.

I don’t why but right know it’s not happening.

Thanks.

https://discourse.mcneel.com/t/how-to-ask-effective-questions/50034/2

You are looking for Flip Matrix, btw is this a homework assignment? See that here also - Better than list item?