From noon until sundown for the past three weeks, Alicia Cosnahan has sloshed bold-colored acrylic paints on an exterior wall of Wisdom, a bar two blocks from John Philip Sousa Bridge.

Most afternoons, after school let out, a few local high school students grabbed paintbrushes and joined the artist in her work. A five-year-old, whose parent works at a Chinese restaurant down the street, was also invited to leave her mark on the wall.

With the help of surrounding community members, Cosnahan, who goes by her artist name, DECOY, is putting the finishing touches on Capitol Hill’s newest mural at 1432 Pennsylvania Ave. SE.

The 1,200-square-foot piece of art depicts Sousa, the famous U.S. Marine Band conductor and Capitol Hill resident, and his band as silly cartoon characters behind a hot-pink backdrop.

A black iron-rod fence runs behind the men in the picture, much like the fences all over the Hill. The mural is decorated with the words, “Welcome to Capitol Hill.”

It’s a big change for the formerly dismal and empty parking lot.

But the gigantic art display is more than a welcome sign; it’s also a crime deterrent. The mural is one of 22 created for MuralsDC, an art program that seeks to prevent graffiti vandalism.

MuralsDC was formed in 2007 in a collaboration between D.C. Councilmember Jim Graham’s office, the Commission on the Arts and Humanities, the Department of Public Works and youth group the Midnight Forum in an effort to abate illegal tagging.

“It’s kind of a code of honor among graffiti artists,” said Nancee Lyons, a spokeswoman for the Department of Public Works. “Artists tend to refrain from defacing another artist’s work, so the murals prevent vandalism. We also take graffiti artists and pair them up with young locals who may be doing this illegally. That way they can still create public art, legally this time.”

The project is funded at a tenth of the annual $1 million price tag that the city usually fronts for painting over illegal graffiti. Lyons said the less-expensive alternative is not only more fun, it’s more successful at deterring tagging. Whereas graffiti artists often repaint over the city’s efforts to cover their bright designs, areas with the murals have seen a “dramatic decrease in vandalism,” she said.

Each mural is selectively placed in an area with a tagging problem. Lyons said there’s one in every ward of the city — except Ward 3, where graffiti isn’t an issue — and five additional murals will be completed by the end of the month.

After a space is designated for a mural, the artists research the surrounding areas and speak with residents and local businesses to determine what images have sentimental values to locals. In her experience with mural painting, Cosnahan said communities especially appreciate public art when it’s locally connected or when people who live in the area have a hand in the painting. She chose Sousa, writer of “The Stars and Stripes Forever,” for example, because he’s the local claim to fame.

Cosnahan said her mural on Wisdom’s wall had two “community days” that allowed children, mostly high school students, to work on the project. Even biking participants of the recent Hill and Go Seek race contributed to the mural.

Originally the mural was planned to be half its current size, Cosnahan said. But the enthused artists wanted a bigger palette and ended up painting almost the entire wall of the parking lot.

Her sense of humor also shines through in the mural: People don’t often mix hot pink with military depictions, and each member of the band will have an exaggerated mustache or facial hair.

Cosnahan sees her work as a way to bring art to locals.

“Most people don’t know which gallery is opening on Thursday, and they’re probably not going to the Mall to see the newest art exhibits,” she said. “So art on the street is the only art they know.

The best part, however, is the life it gives to the community and passers-by, she said.

“Something like a giant, happy, pink mural inside a gray parking lot brings a happy little mood to the street,” Cosnahan said.