# The Mathematical Beauty of Simplicity

One of the universal laws of nature is the law of the least rate of energy expenditure. Thus, for example, the light emitted from point A chooses the path that requires the least amount of energy among the infinite number of routes to go to point B, which is often also the fastest.

If points A and B are in the air, the light follows the AB line because the AB line is the way light will reach point…