Figure 4. Coalescence of liquid metal-based soft robots. (a) Scheme and photographs of merging droplet robots. (b) Coalescence of liquid metal droplets in a line pattern. (c) Coalescence of liquid metal droplets in a rectangular array pattern. (d) Merging of liquid metal droplets, which are arranged to signify the letters S, Z, and U. The surrounding medium is in these experiments alkaline water.