If you reject studying human anatomy, art of drawing, conceptions of perspective, mathematic rules of aesthetics and colour I would rather say that it is a manifestation of laziness and not that of a genius.
Drawing - Depiction of shapes and forms on a surface chiefly by means of lines. Color and shading may be included. A major fine art technique in itself, drawing is the basis of all pictorial representation, and an early step in most art activities. Though an integral part of most painting, drawing is generally differentiated from painting by the dominance of line over mass.
The artist's choices of drawing media-- tools and surface-- tend to determine whether a drawing will be more or less linear or painterly in quality.
There are many sorts of drawing techniques, varying according to the effect the artist wants, and depending on whether the drawing is an end in itself-- an independent and finished work of art-- or a preliminary to some other medium or form-- although distinct from the final product, such drawings also have intrinsic artistic value. Preliminary drawings include various exercises (e.g., contour drawing, gesture drawing, figure drawing, drawing from the flat), as well as sketches and studies, cartoons and underdrawings.
Drawing has been highly appreciated since the Renaissance, greatly because it implies spontaneity-- an embodiment of the artist's ideas. This spontaneous idea has always been used to particular advantage in caricature. The invention of printmaking techniques in the fifteenth century made possible the duplication and dissemination of drawings, further establishing drawing as a definitive art form.