Answer:
The Caddo’s wall sets the theme that "if you do not build positive relationships with others, you will find yourself alone".
Kaddo became proud when he build the wall and thus he used to treat the other persons in harsh manner. He would sit on his wall and then talk to persons and give them advice. His attitude was not positive towards the villagers and thus he was left alone at the time of failing harvests.
Nothing good will come from greediness and power. Hope this helped :)
