It's common to add grass to the sections and elevations you are drawing. You want it to match the graphic style of your section. With this command a polyline is added that adds grass in an abstract style with spikes. It's drawn along linear entities you've selected so it will follow any angle or curve. You change the size and the distance between the new polyline of spike grass and the selected linear entity. If the new polyline appears below the selected linear entity you can either use AutoCAD's native reverse command on that linear entity or use the flip function of the command so the new polyline will appear above the selected entity.