Box Object

### 3.2.1 Box Object

The `box` is one of the most common objects used. We try this example in place of the sphere:

      box {
        <-1, 0,   -1>,  // Near lower left corner
        < 1, 0.5,  3>   // Far upper right corner
        texture {
          T_Stone25     // Pre-defined from stones.inc
          scale 4       // Scale by the same amount in all
                        // directions
        }
        rotate y*20     // Equivalent to "rotate <0,20,0>"
      }

In the example we can see that a box is defined by specifying the 3D coordinates of its opposite corners. The first vector is generally the minimum x-, y- and z-coordinates and the 2nd vector should be the maximum x-, y- and z-values however any two opposite corners may be used. Box objects can only be defined parallel to the axes of the world coordinate system. We can later rotate them to any angle.

Note: we can perform simple math on values and vectors. In the rotate parameter we multiplied the vector identifier `y` by 20. This is the same as <0,1,0>*20 or <0,20,0>.