Design and verification of the self-folding crease. (A) The layout of the self-folding crease. (B) The self-folding process triggered by heat. (C) The self-folding process is characterized by the final crease angle (\(\Theta\)) as a function of \(L_{gap}/L_1\). (D) The photographs show three folded configurations controlled by \(L_{gap}/L_1\). We use \(L_1=18\) mm for all experimental prototypes.