So, you can scribble, right? Do you know that that simple scribble can make shadows depending on how light or dark you make them, which direction they go and even with the addition of curves? That is pretty much all there is to shading to make your straight line drawing look more 3-D.

This example is called ‘cross hatch’. Guess why. Yes, because the lines criss-cross over each other in all directions. This is another way to make shadows, or shading and shading is what creates depth in a flat picture.

And more cross hatch styles. Any type of shading where the lines cross each other are the same thing. The more you add crossed lines the darker the shading. Why so dark? Think about it. Look at any object with the light coming from where you are. Notice the areas that are the furthest away, the outer edges. The farther away, the darker, the closer the lighter. That is the very basics of drawing.