Having established a material pool with varying Young's moduli and crystal sizes, we performed force measurements by sampling from this material pool using Bayesian optimization (Figure ). The measured Young's modulus was used as an identifier for the crystals, using values obtained from bending tests. Crystals of compound 7 were excluded from the entries as the modulus overlapped with that of compound 4, and crystals of compound 6 were also excluded due to their small size. This resulted in eight crystal entries. The ranges of crystal sizes and light intensities are described in the Supplementary Methods. Once a crystal sample was selected, blocking force was monitored under light irradiation from above or below the crystal.