The article explores the use of the moiré effect to design and manipulate topological defects in nematic liquid crystals (LCs). By rotating two substrates with periodic surface anchoring patterns, the researchers observe a variety of tunable topological defects. These defects can guide the three-dimensional self-assembly of colloids and influence defect behavior by preventing self-annihilation through jamming. The study demonstrates that nematic moiré cells can generate arbitrary shapes through defect regions, enabling applications such as defect-directed self-assembly, material transport, micro-reactors, photonic devices, and anti-counterfeiting materials. Nematic LCs consist of rod-like molecules that can self-assemble into mesoscopic structures with long-range orientational order. Topological defects in these systems can segregate foreign molecules and particles, leading to applications in directed self-assembly, photonic devices, biosensing, and material transport. Existing methods for manipulating defects include magnetic and electric fields, optical control, active stresses, and patterned substrates. However, these methods are limited by the intrinsic symmetry of the system and the imposed pattern. Inspired by twistronics, the researchers propose using the moiré effect to engineer mesoscopic structures in LCs. By rotating one surface relative to another, they create a nematic moiré pattern that can generate a rich variety of periodic disclination structures, including straight lines, helical-like curves, defect networks, and loops. These structures are modeled by continuum simulations and confirmed by confocal microscope experiments. The geometry of these structures is sensitive to twist angles and cell gaps, revealing both low- and high-frequency modes of the geometric moiré. The study also shows that defect lines can guide the self-assembly of colloidal particles, opening up possibilities for interparticle and assembly behaviors. The researchers demonstrate that certain nematic moiré patterns can generate pixelated shapes represented by defect regions, offering a versatile platform for investigating the interplay of topology, geometry, and ordering in LCs and other soft materials systems. The findings suggest that nematic moiré patterns can be used for inverse design of mesoscopic structures, enabling applications in printing, self-assembly, photonics, and anti-counterfeiting materials. The study also explores the response of nematic moirés to external electric or magnetic fields, showing that they can undergo the Frederiks transition under certain conditions. The results highlight the potential of nematic moiré patterns in various applications, including displays and responsive materials.The article explores the use of the moiré effect to design and manipulate topological defects in nematic liquid crystals (LCs). By rotating two substrates with periodic surface anchoring patterns, the researchers observe a variety of tunable topological defects. These defects can guide the three-dimensional self-assembly of colloids and influence defect behavior by preventing self-annihilation through jamming. The study demonstrates that nematic moiré cells can generate arbitrary shapes through defect regions, enabling applications such as defect-directed self-assembly, material transport, micro-reactors, photonic devices, and anti-counterfeiting materials. Nematic LCs consist of rod-like molecules that can self-assemble into mesoscopic structures with long-range orientational order. Topological defects in these systems can segregate foreign molecules and particles, leading to applications in directed self-assembly, photonic devices, biosensing, and material transport. Existing methods for manipulating defects include magnetic and electric fields, optical control, active stresses, and patterned substrates. However, these methods are limited by the intrinsic symmetry of the system and the imposed pattern. Inspired by twistronics, the researchers propose using the moiré effect to engineer mesoscopic structures in LCs. By rotating one surface relative to another, they create a nematic moiré pattern that can generate a rich variety of periodic disclination structures, including straight lines, helical-like curves, defect networks, and loops. These structures are modeled by continuum simulations and confirmed by confocal microscope experiments. The geometry of these structures is sensitive to twist angles and cell gaps, revealing both low- and high-frequency modes of the geometric moiré. The study also shows that defect lines can guide the self-assembly of colloidal particles, opening up possibilities for interparticle and assembly behaviors. The researchers demonstrate that certain nematic moiré patterns can generate pixelated shapes represented by defect regions, offering a versatile platform for investigating the interplay of topology, geometry, and ordering in LCs and other soft materials systems. The findings suggest that nematic moiré patterns can be used for inverse design of mesoscopic structures, enabling applications in printing, self-assembly, photonics, and anti-counterfeiting materials. The study also explores the response of nematic moirés to external electric or magnetic fields, showing that they can undergo the Frederiks transition under certain conditions. The results highlight the potential of nematic moiré patterns in various applications, including displays and responsive materials.