getting the curve start point and end point layer

hello, im having a problem with matching the points of the curves i have in grasshopper to their layers in rhion. why am i doing this? i need to pass on all the curves i have and if they connect between the specific layer that i want then this joined triangle curves i want to put in a list. :\ i tried to do it in python. but didn't work because i cant find the right way to write it. 

in the attached file i want to find the curves that connect between layer marks1 . and get their triangle. 

thank u a lot !!