Adding arrows is an excellent technique that designers use to illustrate the functionality of a design. Andres has done a fine job of presenting the functionality of this sketch table by keeping the lines of the table clean. Allowing the viewer to focus on both the design of the table and on its functionality. He has used arrows to convey that the drawing surface rotates, the drawers flip out, and that the desk can adjust in width to suit the user. Lightly coloring the arrows conveys that the designer considered both the design and functionality of the concept. Andres also grounded the sketch by using a block of color behind the sketch, which adds depth and visual weight to the composition. This technique also adds another layer of consideration that clients enjoy seeing.