Before revision:  When actuated by an externally applied magnetic sawtooth field, the robot demonstrated stick-slip motion enabled by its rockers. The controllable bidirectional motion is enabled by adjusting the DC offset of the waveform, which tilts the robot and biases it towards either forward or backward motion .
After revision:  When actuated by an externally applied magnetic sawtooth field, the robot demonstrated stick-slip motion in the predisposed direction, dictated by the neutral position tilt .