“Parallel straight lines are straight lines which, being in the same plane and being produced indefinitely in both directions, do not meet one another in either direction.” Euclid’s Elements, Definition 23
The wall near Murin-an has a drawing of parallel lines made by rain.
Euclid was here too!
I could see the lines melt and dissolve into the wall. I imagine them wanting
to “hold hands” and meet after all.