source image : www.graffiti-alphabet-letters.com 
Graffiti and graffito are from the Italian word graffiato. Graffiti is applied in art history to works of art produced by  scratching a design into a surface. A related term is "graffito," which  involves scratching through one layer of pigment to reveal another  beneath it. This technique was primarily used by potters who would glaze  their wares and then scratch a design into it. In ancient times  graffiti was carved on walls with a sharp object, although sometimes  chalk or coal were used.
These illustrations were often placed in ceremonial and sacred locations  inside of the caves. The images drawn on the walls showed scenes of  animal wildlife and hunting expeditions in most circumstances. This form  of graffiti is subject to disagreement considering it is likely that  members of prehistoric society endorsed the creation of these  illustrations.
The modern day graffiti artist can be found with an arsenal of various  materials that allow for a successful production of a piece. Spray  paint in aerosol cans is the number one necessity for graffiti . From  this commodity come different styles, technique, and abilities to form  master works of visual graffiti. Spray paint can be found at hardware  and art stores and come in virtually every color.
Modern experimentation ,modern graffiti art often incorporates  additional arts and technologies. For example, Graffiti Research Lab has  encouraged the use The only known source of the Safaitic  language, a form of proto-Arabic, is from graffiti: inscriptions  scratched on to the surface of rocks and boulders in the predominantly  basalt desert of southern Syria, eastern Jordan and northern Saudi  Arabia. Safaitic dates from the 1st century