My Unmade Bed
Contour drawing is different from outlining. An outline demarcates the farthest perceivable edge of the subject. It appears to be attached as the outer edge of the subject, separating it from its surroundings. Typically, outlines are of uniform thickness and they have a tendency to flatten the image, emphasizing the two-dimensional space within the line.
By contrast, contour lines should be conceived of as being attached to the form and existing just inside the farthest perceivable edge. Contour lines typically vary in weight (i.e., thickness and darkness), thereby conveying information about the three-dimensional surface upon which they reside. Thus, contour drawing is a form of "modeling" that is independent of shading.
Complete a contour drawing of an unmade bed. Review these examples of contour drawings before beginning. Create a sense of atmospheric depth by varying the weight of your line such that the farther reaches of your subject are lighter than the nearer. Also, attempt to convey something of the materiality of your subject using line quality.