a, Design software for complex DNA brick structures. Desired shapes can be designed by editing voxels through a 3D interface (top), which are then translated to strands (middle) and assigned sequences (bottom). b, c, Cavity shapes can be generated by selecting or excluding (right) voxels to approximate 3D-rendering files (b) or to satisfy mathematical equations (c); see Supplementary Information sections 9.3, 9.4 for design details. b–n, Diverse cavity shapes. For each design, the diagram at the top depicts a 3D model of the designed shape. Expected projections (top in b–d; left in e–n) and averaged TEM images (bottom in b–d; right in e–n) are also shown. The individual particles used in averaged images are depicted in Supplementary Table 3 and Supplementary Figs 77–82. All scale bars, 100 nm.