(خط کشیدن (دور
to draw a line (around)
... is the easy image--the visualization of a purposeful (and complete) mental boundary.
Perhaps the closest equivalent in English is to draw a line under. To move on.
But the horizontality weakens the resolve. The air above this line is empty, after all, leaving plenty of room for relapse, for negotiation.
What can be more conclusive, more reflective of the twin concepts of closure/enclosure than a perfect circle of finality...
