Figure 3. On-demand splitting of the LM composite robots. (a) Schematic illustration of the on-demand splitting of the LM composite robots by the use of a circular magnet. (b) Simulation result showing the magnetic field distribution of a circular magnet (outer diameter is 3.5 cm, inner diameter is 1.5 cm, height is 0.5 cm) before and after rotation (Top view). (c-e) Photographs of the splitting process of the liquid metal soft robot into separate sub-droplets on an acrylic sheet filled with alkaline water: (c) two sub-droplets, (d) three sub-droplets, and (e) eight sub-droplets.