 'Pigtail' eye bolts are a form of bent loop where the ends are not closed, but multiple turns are used to prevent a rope slipping out.They allow a rope to be threaded into the loop, even if its ends are already attached elsewhere.Feminist artist Sheila Levrant de Bretteville designed a necklace of an eye bolt on a chain, meant to represent "strength without a fist"; she gave the first of these to Arlene Raven and Judy Chicago when they started the Feminist Studio Workshop in 1972.