How do organs reach their reproducible shapes? This question remains open because it has been difficult to connect the microscopic dynamics/stochasticity to the macroscopic regulation/reproducibility at the molecular-cellular-organ level. We challenged by data science to quantify the heterogeneity of microtubule alignments to connect the molecular dynamics to the regulation of cell shape, and to quantify the variability of cell growth to connect the cellular stochasticity to the reproducible organ shape. Our key and counterintuitive result was “cellular randomness is required for reaching the correct organ size and shape” meaning that the order can be emerged from disorder.