i belive the answer to be etching
please let me know if this helps!
Answer:
an introduction to the members of the lin family
Explanation:
I believe that element is called
flying buttresses.
Flying buttresses support the walls of a building and given that they are quite slanted, they seem as if they are forming an arch with that particular wall they are leaned against. I've attached an image of them for you to see what I mean.