Flyaway Productions, an apparatus-based dance company, celebrates its 20th anniversary with the premiere of “Grace and Delia are Gone” at Fort Mason Center for Arts & Culture. A site-specific dance piece at the Firehouse, the work is set to a commissioned score by Carla Kihlstedt and Matthias Bossi, with set and rigging design by Sean Riley, and lighting design by Matthew Antaky. The piece explores the issue of violence against women through the lens of murder ballads.