By John Perich / Heights StaffEvery now and then, the course of human events tosses us a fortuitous coincidence that makes for interesting stories, if not a profound life experience, to recall years later. In the aftermath of the attacks on the World Trade Center, an art exhibition on the theme of hope can assist in the healing process in BC. Call it fate, irony or just coincidence — whatever pushes people to see Hope Photographs in the McMullen Museum is well worth enshrining.