Given the task definition and input, reply with output. You are given a background paragraph that describes one or more causal or physical relationships, such as a relationship in economics, scientific law, or nature. You need to come up with a fictional story that makes use of the concepts or the relationship described in the provided paragraph. Make sure that your story does not repeat the relation in the given paragraph (e.g., by avoiding verbatim copies of the given paragraph). Start by reading the background paragraph, and determine what relationship(s) are in the paragraph. Write a story that involves the relationship(s) that you determined are in the background paragraph. Try to use your own words as much as possible and not repeat the background paragraph. Feel free to make up places and events as long as they tie back to the background paragraph in a way that you can ask a question about.

Background Paragraph: There are two basic types of energy in the universe: potential energy and kinetic energy. Potential energy is stored energy that is available to do work, but it has not yet been released. The wood in a fireplace possesses potential energy. It is available for producing heat, but has not yet been ignited, so it is not releasing heat into the surrounding environment. Kinetic energy is the energy of motion. A waterfall is an example of kinetic energy. The moving water can erode the rocks in the stream, wearing them down into smaller particles. This same water motion can turn a turbine to generate electricity. In both cases, the movement of the material (water) causes work to be done.
While out on a hiking trip Ricky stumbles upon a waterfall. While looking at it he notices that the rocks around and behind the waterfall as well as the rocks in the stream it flows into are smooth, When he is no longer near the waterfall the rocks are very jagged and cracked and sharp.