New photo imaging techniques on computers allow artists to distort an image from its original shape. Figure 1 is a square image. Figure 2 is stretched 4 units wider and shrunk 4 units shorter than figure 1. How many square units greater is the area of figure 1 than the area of figure 2?
If the square has x units on a side, then the distorted square has area
(x+4)(x-4) = x^2 - 16
so, a difference of 16