Material-producing organoids can not only produce better materials, but also improve manufacturing techniques. Bringing fabrication to microscopic scales has enabled pattern-driven material microstructures 589 and miniaturized devices, revolutionizing everyday lives 590 . For instance, photolithography has supported the semiconductor industry, telecommunication, modern computing 590 , and brought microelectromechanical systems (MEMS) 591 , sensors 592 and implants 593 . However, both manufacturing costs 594 and production volumes 595 are constrained by available technologies. In contrast, nature achieves complex selfmicrofabrication in large sizes and at low costs 596 through selforganization (Fig. ). Engineering material microstructure in bulk materials can enhance their mechanical properties, as demonstrated in hierarchical materials 597 . For instance, while chemically similar to chalk 598 , bivalve shells are up to 100 times tougher (3.3 to 9