The rock cycle is an idea used to describe the way that rocks change from one type (igneous, sedimentary, and metamorphic) to another through geologic processes over time. Weathering, erosion, and the movement of tectonic plates under the Earth's surface are responsible for these changes.
As you view the picture, know that it is meant to be read in all directions.
Image: The Rock Cycle
Source: The Rock Cycle (sfcollege.edu)