Fig. S10. The measured rolling speed plotted against different rotating frequencies of \(\vec{B}\). Each data point had five trials and the error bars represented their corresponding standard deviation. The solid red line and dashed blue line represented the best fit line for the data points pertaining to rolling along the MMR’s length and width, respectively. Because higher speed could be achieved when the MMR was rolling along its length than rolling along its width, the gradient of the solid red line was steeper than its dashed blue line counterpart.