By bending your mirror in various directions, you can observe how it is distorting the world around you. Ideally, you should find an environment that has a distinct horizon, 'sky' and 'ground' to simplify your observation. Try going outside.

If you roll the sheet into a horizontal cylinder, you can see that the reflections are compressed vertically, and begin to appear long and thin. Roll the sheet into your hand to form a hollow half-cylinder. The reflections have compressed in the same manner, but now reversed, with the 'sky' reflected in the lower half, and the 'ground' in the upper.

Now turn your original cylinder vertically. You will notice that any roughly horizontal line below your eye level in the environment will appear to 'climb' or bend upward in its reflection as it goes away from you, and hence toward the vanishing point on the horizon. The opposite is true of lines above your eye level. As well, any subtle variations in the height of what is being reflected around you become drastically exaggerated as they are compressed by the curvature of your cylinder.

These simple observations are the foundation of understanding how complex rounded surfaces distort reflections, and, more importantly, how form can be described by the application of these phenomena to your drawing.

Now take out your 'diffuse' sheet, and bend it into a positive horizontal half-cylinder. Rather than making it perfectly cylindrical, however, pinch it more toward the center so that it forms more of a loose bend through the middle, like a 'v' section on it's side with a rounded point.

You will notice that the area where the sheet is bending brightens up, as the metal-flake in the paint gathers diffused light. You have created what is called a 'bone' in the surface. This phenomena is a very powerful graphic effect, and can serve as strongly as a line to control the balance of your form.

Coning Reflections

Keeping the "pinch" at one end, let your sheet unroll into more of a regular cylinder at the other end. Notice how the highlight 'flares' out and diffuses as the curvature of the bone lessens. You have just created a 'coning' bone in your surface. Coning is also a very powerful tool in surface development, and can be thought of as the three-dimensional equivalent of varying your line weights in a drawing.