Figure S1

Measurement of Young’s modulus of paper. We conducted a total of three tests on paper with dimensions of 100 mm × 15 mm using a desktop type tensile and compression machine (A&D, MCT-1150). The test was conducted until the paper was torn. The load-deflection curves obtained from the three tests were converted to stress–strain curves, and the slope of the elastic region was derived by linear approximation. We defined the elastic region as the strain ranging from 0 to 0.0025. (a) Photograph of tested environment. (b) An example result of the load-deflection curve. (c) The obtained elastic region and its slope. Young’s modulus of the paper used in this experiment was 5.32 GPa. Results from three tests were averaged to obtain the final result.