The linear marks with a pen or brush or the edge created when two shapes meet.
A line which defines a form or an edge. The outline or silhouette of an object or figure.
Contour lines can be used to show any dramatic changes of a plane within the object or form. (like the inner seams within the structure of a shoe, for example).
https://study.com/academy/lesson/contour-line-in-art-definition-examples.html
KQED: Elements of Art - LINE
Watch the video.
Answer the questions during the video.
https://edpuzzle.com/assignments/5f347783230c643f19dba3b6/watch