The island of Isola is in danger in "Virtual Villagers: The Tree of Life," the fourth game in the "Virtual Villagers" series. Your tribe members stumble upon a majestic but dying tree, and they surmise that they can save the entire island if they restore this tree to life. One of the early puzzles involves changing the path of a stream in the village so that it will water the ailing tree. Your villagers must first clear a blockage in the stream and then use an object found in the village to direct the water to flow throughout the entire village.
Drag one or more adult villagers to the debris blocking the stream, located just to the left of the flutes on the cliff.
Drop the villagers on the debris to instruct them to clear it. Remove all of the debris.
Take a villager with trainee or better skills in both science and construction to the large rock, called a keystone, located where the stream had previously ended on the northeast side of the island. She picks up the stone and puts it in the gap to the west of the tree, filling the lagoon and restoring the stream's proper path.
Leave at least one villager at the location of the former obstruction in the stream to keep it free from debris.
If your villagers stop clearing debris from the obstruction, the stream will push more debris into place, completely blocking it again.