Composition helps creating a visual flow or rhythm leading the viewers eye to certain content; but off course, it depends on the culture of the designer and the viewer.
The flow of objects can display Movement, so different patterns and arrangements should be used to creates the proper effect.
The <em>"9 Zone Grid"</em> is about setting up a focal point for a content, or theme, creating tension, movement and emotion; imaginary lines are placed into thirds, vertically and horizontally, making an illusive 9 squares grid.
Rhythm is also the effect caused by changing and swinging the position of items within the grid structure.
Done successfully, the composition should draw the viewer's eye along the content, presenting the main subject.