To make the materials, researchers at Princeton University first made piezoelectric ribbons out of lead zirconate titanate, or PZT. Then they took a slab of silicone-based organic polymer and stretched it out. They added the PZT ribbons, binding the materials together, and then they let go. As the silicon substrate contracted, the PZT buckled, with part of it releasing from the silicone surface. The result was a wavy shape that lets the PZT stretch and contract without breaking.