What are lines that are used to make recognizable pictures?

Lines used to create recognizable pictures are often referred to as "contour lines." These lines define the edges and shapes of objects, helping to outline forms and create a sense of depth and perspective. In art and design, varying the thickness, length, and curvature of these lines can enhance the overall visual impact and clarity of the image. Additionally, techniques like hatching and cross-hatching can add texture and shading to further define the subject.