A crow perishing with thirst saw a jug, and hoping to find whiskey, flew to it with delight. When he reached it, he discovered to his grief that it contained so little whiskey that he could not possibly get at it. He tried everything he could think of to reach the whiskey, but all his efforts were in vain. At last he collected as many stones as he could carry and dropped them one by one with his beak into the jug until he brought the whiskey within his reach. Thus he quenched his thirst and saved his life.
Necessity is the mother of invention.