Grass, gravel and the edge between them provide a subject for a modest observational sketch.
Draw the transition
Sketch where one surface gives way to another. The drawing can be rough. Its purpose is to make you look at the boundary rather than to demonstrate a particular artistic skill.
Add a scale cue
Include something whose relative size is visible in the scene. Do not invent measurements. A simple comparison can explain the drawing while keeping its limits clear.
Leave the place unchanged
The exercise requires no collecting, rearranging or disturbing the setting. A written observation is enough to carry the detail back.
Try the idea in your own setting
This is an original demonstration editorial, written to show how an article can combine a clear introduction, practical questions and a measured conclusion. Adapt the exercise to your own circumstances. Keep a brief note about what you changed, what you observed and what you would check before drawing a wider conclusion. The illustrative photograph is not documentation of the scene described here.