Not all graffiti is illegal. Some can be done in broad daylight, with a whole community proudly watching.
A British-born Muslim artist named Mohammed Ali has coined a unique art form he calls Aerosol Arabic. Inspired by a combination of urban street art and traditional Arabic calligraphy, he decorates large walls with giant spray-painted murals offering messages of hope.
Ali uses the marriage of art and Islam to unite rather than divide, and to enlighten people about his religion.
He recently made a stop in New York during his first tour through the United States. His goal was to paint a mural that said, "From God we came / To Him we shall return," in honor of the 10 people -- including nine children -- who died in a horrific fire last month in the Bronx.
A space heater started the fire, which rushed through the house packed with family members from two Malian immigrant families. It was the city's deadliest fire in two decades.
When Ali came through the same neighborhood, a place still very much suffering the emotional wounds, many of the surviving family members came out to help put paint to brick. Giddy children climbed over each other for a chance at the paint. The bright blues and reds of the mural shone defiantly through the light rain.
The merry mural-making also drew large crowds of curious neighbors and even at least one police officer, who got out of his car to shake Ali's hand and exchange thankful words.
"I used to be very disillusioned with the purpose of art," Ali said. "I used to wonder, what benefit does it serve mankind, just drawing a bowl of fruit or a vase of flowers? ... But today I've really changed my opinion on this and now I think it's one of the most powerful mediums to reach out to people. It's a universal language."