This is the base model of a water pump for the Shared Water Resources module.
The turtles do the drawing of earth, sky, and pump. Then the water in the ground is added with the "create groundwater" procedure using recursion. Next, water gets pulled by the force of gravity, slowly percolating through the ground. Plants are added to one side of the simulation, absorbing some of the water falling from the sky. These plants will appear as flowers, which are turtles the leave a trail behind them resembling a flower. The water that reaches the ground then gets drawn up into the pump (and used but this part of the cycle is not shown). Finally, the water is "recycled" as rain, falling quickly through the sky, where it has a chance of evaporating.
We will add "plants" to half of the dirt that some of the water will seep into and return to the sky. The other half will have no "plants"