The mark consists of a circle having 3 upper projecting arms bending partially around the left side of the circle and then extending upward and to the right of the circle as if to grab and pull the circle to the right, and 3 lower projecting arms bending partially around the right side of the circle and under and extending downward and to the left of the circle, as if to grab and pull the circle to the left, and 5 parallel radiating lines extending leftward from the circle from the upper projecting arms and above the ends of the lower projecting arms, and 5 parallel radiating lines extending rightward from the circle from the lower projecting arms and beneath the ends of the upper projecting arms.