Instead of folding, kirigami relies on cuts to change the structure and function of materials. By doing so, a thin, perforated, flat sheet can be transformed into a foldable 3D structure by simply stretching the cut material.
The researchers found that when applying sufficiently large amount of stretching, buckling is triggered. This results in the formation of a 3D structure comprising a well-organised pattern.
If the material is stretched more, the temporary deformations become permanent folds. The pop-up pattern and resulting mechanical properties of the material can be controlled by varying the orientation of the cuts.