Writing on walls is a form of expression that has been around for centuries. It is commonly referred to as graffiti and is often used to express opinions, feelings, or to make a statement. Graffiti is usually done with spray paint, markers, or other materials and can be found on walls, buildings, and other surfaces. It is often seen as an act of vandalism, but it can also be used to create beautiful works of art. Graffiti has been used to spread messages of protest, to commemorate events, and to express creativity.