Fig. 1: Symmetrical triangular origami-kirigami patterns and thick-panel units.

AāC One-, two- and three-layer origami patterns, origami-kirigami patterns and their symmetrical triangular thick-panel units (STTPUs). The blue solid lines represent mountain creases, the red dashed lines represent valley creases, and the green dotted line represents slit creases. D Ratio of change in thickness of STTPUs. E Ratio of change in main surface area of STTPUs. F Ratio of change in total surface area of STTPUs, when the base angles are 60 degrees. GāI The folding sequences of the 3D printed prototypes of one-, two- and three-layer origami-based STTPUs. JāO The folding sequences of the 3D printed prototypes of one-, two- and three-layer origami-kirigami-based STTPUs. The base angles are 60 degrees.