The topological structure of a material can significantly affect its physical properties. For example, nanoparticles, nanowires, and nanosheets composed of the same material are observed to have different properties. In the last decade, scientists have elegantly shown that arrays of oriented nanostructures have desirable properties for high-performance devices. To this end, a wafer-scale, singlecrystalline, (001)-oriented β-Bi2O3 film is converted by Q. Liu and co-workers into a large-area network of nanowalls made of BiOCl, Bi2O2CO3, and β-Bi2O3. On page 2394, the network is further transformed into nested self-similar networks of Bi2S3 in a series of solution processes, directed by lattice matching among the different phases. The superstructures of these bismuth compounds reveal anisotropic electrical conductivity as a result of the oriented growth of nanostructures.