Upstream, Downstream

Once there was a village at the banks of a big, strong river. One day a villager saw a person crying for help being carried down the river. The villager, who was a strong swimmer, jumped in and pulled the drowning person ashore. Briefly afterward, another person was carried downstream, and then another, and another. The villager called his friends for help and they all came and helped. They got really busy and exhausted by more and more people in high distress in the river, and then fighting for their lives to save others in the currents day after day. So the villagers invented a net that was cast across the river so it would catch people. They built shelters and clinics for the people whose lives they had saved.