Nanoengineers are asking what might be possible if semiconductor materials were flexible and stretchable without sacrificing electronic function? Today’s flexible electronics are already enabling a new generation of wearable sensors and other mobile electronic devices. But these flexible electronics, in which very thin semiconductor materials are applied to a thin, flexible substrate in wavy patterns and then applied to a deformable surface such as skin or fabric, are still built around hard composite materials that limit their elasticity.