An old man was sitting with his educated son in the courtyard. The man asked his son four times what a crow sitting on the wall was, and each time the son answered it was a crow. The fourth time, the son responded with irritation. The father then showed his son a diary entry, where it described the son as a child asking what the crow was 25 times, and the father responding each time patiently and without irritation. The father explained the difference in temperament and patience between a father and son.