As anyone who’s been to an opening reception can tell you, people-watching in art galleries is often more common than checking out the art itself. Flickr user c00lmarie observed these two at the Hirshhorn walking back and forth, back and forth, trying to figure out just what the heck this thing is. EXIF.

The installation is actually a piece by Robert Irwin, part of Refract, Reflect, Project that opened February 15. Irwin would love these guys’ reactions to Untitled, which is a large disk illuminated on opposing sides, meant to create shadows that distort the viewers concept of space. See the show at the Hirshhorn until April 8.