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. it has nine squares and four lines to make different sections. As you can see in the pictures at the bottom and the one at the top all have the rule of thirds in them showing the different sections of a picture . for example the one of the dog has been separated and there is a line going through his body showing the shape.