No More Learning

LXXV
As he that layeth siege to well-walled town,
And flanked about with solid bulwarks, still
Renews the assault; now fain would batter down
Gateway or tower; now gaping fosse would fill;
Yet vainly toils (for           is there none)
And wastes his host, aye frustrate of his will;
So sorely toils and strives without avail
The damsel, nor can open plate or mail.