Y-Zipper: 3D Printing Flexible-Rigid Transitions in One Click

Inspired by a 1985 patent from MIT Professor Bill Freeman, the Y-Zipper is a three-sided fastener that seamlessly transitions objects between flexible and rigid states. Using multi-material 3D printing and custom design software, we've transformed this 40-year-old idea into a practical tool for rapid assembly. What can Y-Zipper do? ✓ Pitch a camping tent in 80 seconds (vs. 6 minutes manually) ✓ Create adjustable medical casts that loosen during the day and tighten at night ✓ Build adaptive robotic legs that change height on demand ✓ Enable dynamic art installations that "bloom" at the push of a button The system survived 18,000+ zip/unzip cycles in durability tests and can be customized for different shapes: straight, bent, coiled, or twisted. Team: Jiaji Li, Bill Freeman, Stefanie Mueller, and colleagues at MIT CSAIL Presented at: ACM CHI 2026