Scribblings on the walls of buildings

• The writing on the wall
• Unwanted art
• Scrawl on a wall
• "American ___" (1973 coming-of-age film starring Ron Howard)
• The writing on the wall?
• Writings on a bridge, e.g

Wikipedia Word definitions in Wikipedia
Graffiti is a computer program which makes conjectures in various subfields of mathematics (particularly graph theory ) and chemistry , but can be adapted to other fields. It was written by Siemion Fajtlowicz at the University of Houston . Research on conjectures ...

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun COLLOCATIONS FROM CORPUS ■ NOUN artist ▪ Do you think of yourself as a latent graffiti artist ? ■ VERB cover ▪ When the camera crew arrived three days later, the shelter was covered in graffiti and all its glass had been shattered. ▪ The place is covered ...