Figure 2b presents the self-folding process of the SCS with four creases. Immediately after printing (Figure 2b(i)), mountain folds are formed on the prior-printed side. Given that both sides cannot be printed simultaneously, there is a time lag between the folding times of the mountain folds and the valley folds due to the time required to set the printer. After 60 s (Figure 2b(ii)), the side printed subsequently starts to fold. After 600 s (Figure 2b(iii)), folding on both sides is completed, and the SCS is formed with the mountain and valley folds (Figure 3). Figure 2c presents the self-folding process of the SCS with the number of creases increased to 10 (Figure 4).
Figure 2d presents a demonstration, wherein the paper is transformed into an SCS with increased stiffness. The central part of the structure is fixed to a wooden board with double-sided tape. As shown on the left side of the figure, the sheet of paper without the SCS cannot withstand its self-weight and bends downward. Conversely, as shown on the right, the SCS structure can support its own weight without deflection. The SCS improves the second area moment and stiffness of the paper. Furthermore, a number of SCS sheets can be stacked to increase the stiffness without occupying significant space. Figure 2e presents a demonstration of the stacked SCS, wherein an SCS stacked with 10 sheets withstands a mass of approximately 4 kg (Figure 5).