As advanced as modern machines are, the building blocks have changed little since the industrial revolution, leading to rigid, bulky, and complex devices. Future machines will include electromechanical systems that are soft and elastically deformable, lending them to applications such as soft robotics, wearable/implantable devices, sensory skins, and energy storage and transport systems. One key step toward the realization of soft systems is the development of stretchable electronics that remain functional even when subject to high strains. Liquid-metal traces embedded in elastic polymers present a unique opportunity to retain the function of rigid metal conductors while leveraging the deformable properties of liquid-elastomer composites. However, in order to achieve the potential benefits of liquid-metal, scalable processing and manufacturing methods must be identified.