Illustrators. By definition, illustrators demonstrate the verbal messages they accompany. Waving a hand to say "hello" is an example of an illustrator. Illustrators are also used to communicate dimensions or direction. When asked to describe the length or width of an object, a person might hold out her hands or separate her thumb and forefinger to illustrate the measurement.
Strong beliefs. Most(especially recent) riots have been because of something political. A lot of riots start off as peaceful protests, but due to other factors such as unnecessary force by police and people joining the protests to turn them into riots for their own gain.