It’s unlikely that artist John Craig Freeman could have gotten permission to build a memorial to the victims of the Sandy Hook massacre in front of the U.S. Capitol. But a virtual memorial he could do, no permit necessary.

That’s the idea behind “Manifest.AR” at the Corcoran College of Art + Design’s Gallery 31. “AR” stands for “augmented reality,” and Freeman and others in the Manifest.AR collective use the tools of virtual reality to superimpose art onto the real world.

Download an app on your smartphone or tablet, stand in front of the Capitol and point the device’s camera in the right direction, and you’ll see Freeman’s “eMorial”: Twenty children’s backpacks and six apples representing the shooting victims (students and teachers), superimposed on the grassy mall. The app uses geolocation and image-recognition software to achieve the visual trick.

The Manifest.AR collective is known for guerilla artwork. In 2010, it held an unsanctioned show at the Museum of Modern Art in which users who had downloaded the group’s app could use their mobile devices to view the artists’ work on MoMa’s walls.

Here, the nation’s capital becomes a backdrop for the artists to explore issues of freedom and democracy, with viewers able to ponder the works around the city, says Joe Hale, the Corcoran’s director of college exhibitions and the show’s organizer.

“There’s a lot of talk about a digital world, a virtual world, like it exists in some separate area — we talk about ‘the cloud,’ ” says Hale. “But it’s not really something remote at all; it’s completely integrated into everybody’s life.”

“Shades of Absence: Governing Bodies”: More than 20 years ago, under pressure from Congress, the Corcoran canceled a planned exhibition of controversial photographer Robert Mapplethorpe’s works. Now, visitors can use an app to view the silhouettes of Mapplethorpe and fellow censored artist Paul Cadmus inside Gallery 31 and in the Corcoran Gallery of Art’s atrium, as well as in the U.S. Capitol building and the National Endowment for the Arts’ home in the Old Post Office Pavilion.

“Sky Petition City”: In Will Pappenheimer’s interactive piece, viewers use a mobile app to draw virtual skywriting messages (complete with airplane sounds) above pictures of such D.C. landmarks as the FBI building and the Supreme Court. The messages are then transferred onto a virtual sky above the Washington Monument. Viewers pointing their smartphone cameras there will see a constantly changing stream of other users’ ideas.

Corcoran College of Art + Design, 500 17th St. NW; through Sept. 1, free; 202-639-1800. (Farragut West)