Rule of thirds intersection of two of the lines, close enough to take advantage of the rule. The rule of thirds is applied by aligning a subject with the guide lines and their intersection points, placing the horizon on the top or bottom line, or allowing linear features in the image to flow from section to section. The main reason for observing the rule of thirds is to discourage placement of the subject at the center, or prevent a horizon from appearing to divide the picture in half. Michael Ryan and Melissa Lenos, authors of the book "An Introduction to Film Analysis: Technique
Rule of thirds not just for dividing the frame, but also for "all" division of straight lines, masses, or groups. On the other hand, he does not discuss the now-common idea that intersections of the third-lines of the frame are particularly strong or interesting for composition. Rule of thirds The rule of thirds is a "rule of thumb" or guideline which applies to the process of composing visual images such as designs, films, paintings, and photographs. The guideline proposes that an image should be imagined as divided into nine equal parts by two equally spaced horizontal lines and two equally spaced vertical lines,