The hip hop graffiti artists began working collectively, both in order to evade police and build larger, more complex pieces. Groups were known as "crews" (just like in other elements of hip hop) and soon began experimenting with different styles, such as bubble lettering and the inclusion of names. Initially, permanent markers were used for the insides of trains, though spray paint soon became the most popular method for coating the exterior. Not only were they easy to conceal, spray paint cans also allowed artists to put up new pieces quickly; thus spreading their name while evading the Transit Authority. In addition to adding their signatures, graffiti artists storve to outdo each other by incorporating different colors and techniques.
