def drag(self, v):
"""
- Drag this polygon along the line v = (x2-x1, y2-y1), and
+ Drag this polygon along the vector v = (x2-x1, y2-y1), and
return the new polygon consisting of the union of all points
- that I've contained along the way.
+ that we've contained along the way.
"""
terminal_p = self.translate(v)
dv_rect = self.drag_rectangle(v)