Another early influence on aerial modern dance, Terry Sendgraff, is credited with inventing the "motivity" trapeze. Sendgraff actively performed, choreographed and taught in the San Francisco Bay Area from the early 1970s, until announcing her retirement in 2005 at the age of 70, when she handed over her aerial dance business to Cherie Carson. The motivity trapeze came about as a result of an exploration on a low-hung circus trapeze. The ropes twisted together, causing the apparatus to spin. By formalizing this, hooking both ropes to a single point of attachment, Ms. Sendgraff used the apparatus to spin, twist, as well as fly in a straight line and in a circle.