Dynamic lines can be used to monitor the distribution of the visual weight of elements in busy settings. Dynamic lines are a characteristic of an urban setting and they interact with the static lines. People are generally the most interesting of the dynamic lines and, naturally interact against common static lines, such as streets, walkways, trees, and columns. Understanding how static elements provide visual backdrops is helpful when planning compositions and evaluating dynamic scenes as they develop. Convergence and divergence of dynamic lines can add or reduce emphasis in an image. This is a technique that can be particularly useful in dealing with people in groups and crowds.