What principle does the rule of thirds illustrate?

The rule of thirds illustrates a method for dividing the screen into sections for composition by breaking the frame into a grid of nine equal parts using two horizontal lines and two vertical lines. This guideline suggests that important compositional elements of the scene should be placed along these lines or at their intersections, rather than centered in the frame. This creates a more visually appealing and dynamic composition that draws the viewer's eye naturally across the image.

Using this method helps to guide the viewer’s attention and can also enhance the balance and harmony of a shot. By positioning key elements along these lines, you can create tension, interest, and movement, leading to a more engaging visual experience. This technique is widely used in photography and videography to improve the overall aesthetic of the image.