Movie S1.

Deformation of creased helicoids made from poly(caprolactone) with a rigid indenter under constrained boundary conditions at the “straight” edge. A continuous hinge-like deformation is demonstrated by crease with zero normal curvature (KN=0) along (i) generating line (straight), and (ii) orthogonal to it (helical), whereas a snap-through instability is observed for crease along (iii) a curve with finite normal curvature (KN≠0). High-speed video of snap @ 3,000 frames per second (fps) included.