The walls of our cities are becoming canvases for creative expression in the hands of a new generation of artists. These kids are street-smart and engaged. (And, OK, they’re not all kids.) They work, on some levels, in the same spirit as Occupy Wall Street, reclaiming and transforming the urban landscape, and infusing their art with social and environmental consciousness.

“Street art is showing that there can be these locations and public spaces that are temporarily taken over with artwork — spaces we would traditionally think of as non-art space,” says Martin Irvine, an associate professor at Georgetown University. Irvine has called street art “the ghost in the urban machine becoming self-aware.”

Over the past few months, we’ve profiled several of these artists in our series, Writing on the Wall — and there are more to come.  Here, we bring you some of the best short films of these artists at work. Throw on your headphones and pretend you’re working …

1. Moose

Here’s “Dr. Dirt,” the street artist Moose, practicing his style of “reverse graffiti” on the walls of the Broadway tunnel in San Francisco:

Want more “reverse graffiti”? Brazillian artist Alexandre Orion scrubbed a gallery of skulls onto the wall of a tunnel in Sao Paolo a few years back. You’ll find a cool video here.

2. Eve Mosher

Here’s New York City artist Eve Mosher talking about her HighWaterLine project, in which she chalked a line around the city demarcating the flood level during (increasingly common) severe storms.

3. Gaia

The artist Gaia is probably best known for his animal-human hybrids that have materialized on the walls of Baltimore. This will give you a glimpse of the streetscape where he works. (I’m sorry, you thought The Wire was pure fiction?)

4. Jetsonorama

A doctor on the Navajo Nation by day, the artist Jetsonorama works on the walls of abandoned gas stations, water tanks, and outhouses in the desert of northern Arizona.

OK, 30-second bonus track. This one speaks for itself.