Before we begin, it’s important that you understand the concept of a 3D world. Start by looking at your monitor. Your monitor screen is actually two-dimensional; you can’t reach in and grab an object on your computer’s screen. So 3D games aren’t really 3D, they just pretend to be 3D by using a variety of lighting and positioning techniques. Take a look at Figure 5.1. Just like the monitor on your computer, the pages of this book are in two dimensions, but we can create the illusion of three dimensions by cleverly using lighting and positioning. Both objects are simple circles, but the one on the right looks three-dimensional because of the lighting applied to it.