Chicago jazz musician Ernest Dawkins has been leading drum circles in parks for four years, an effort supported by the John D. and Catherine T. MacArthur Foundation to amplify the arts and create a healing ritual in the South Side neighborhood. Some sessions take place on planned dates. Others come about more spontaneously after an episode of violence. Police and outreach teams mingle with residents. Dawkins and others play, inviting anyone to pick up a drum to join in. A passerby can take a seat and become part of a moment of community.