Purifying the Tree is the fifteenth puzzle in Virtual Villagers 4. The requirements to solve: Level 3 Dendrology and Puzzle 4. You need an adult that is clean of body and mind to purify the Tree of Life. Drop an adult on the soap in the lab. He will put soap into the pond and suds will appear. Drop the adult into the pond and wait until they are clean. You will know because there will be white sparkles around them. Drop a different adult onto the nursery to move all the children there. Drop the sparkling adult near the wind flutes and they will start to meditate.