The trolley cars were nicknamed Dang Dang cars by Beijingers of old, in reference to the bell at the head of the car that was rung to alert pedestrians.

There have also been several famous non-people that have rung the bell, including Mickey Mouse, the Pink Panther , Mr. Potato-Head, the Aflac Duck and (perhaps most ominously) Darth Vader.

Use Method: lie down on the camber and hook the feet at a rung. put the hands behind the head. Use abdominal muscles to sit up and return to original position. Repeat the same movement.