In the 1960s and 70s, things began to change in America. One thing that started to change is that cities began to get bigger. These major cities like New York City began to grow because their population began to grow. As a result there was more crime. One problem in the 1970s that came to be in New York cities and other major cities were gangs.
These gangs would recruit other people who would have to commit violent acts. Sometimes 1 gang would be against another gang. In order to show their power, a gang wood spray paint graffiti on the walls of buildings in the city. So the other gang could see it and be afraid. Then the other gang would spray graffiti on another building in retaliation.