drawing practices

Four pairs of figures, each pair includes two men with glasses, one sitting and one standing, facing each other. The background of each pair features various abstract or surreal artistic elements.
Line drawing of modern staircase with railing, hanging spherical light fixtures, and artwork on the wall.
Line drawing of a living room with large windows, a fireplace, chairs, a table, a framed portrait, and potted plants.
Line drawing of a mechanical device with a handle, a telescopic arm, and a comb-like attachment.
Close-up of a metallic object with a curved, round section and a flat, textured surface.