Going around in circle

Driving on 15th south on my way to the car inspection station, there is a group of workers in front of the "Old Ebbitt Grill". About 30 of them are chanting and marching in a small ellipse. so elongated that it seems more like two parallel lines of people marching in opposing direction. It is not clear what they are protesting as I can't understand what they are chanting. They are holding bright signs that I can't read from my car.
A peaceful demonstration going in circle.