To evaluate the effect of localized flexibility on body flexibility, experiments were performed using physical half-robot models mounted with the midsection face at x = 0 in the magnetic field created by the actuator magnet (see Figure 2B; magnetic field plots in Figure S1). Body flexibility was determined using the maximum and minimum foot flexion angles for the designs. Foot flexion was measured from a video of the half-robot models being actuated through three rotations of the actuator magnet.