Although DNA is usually billed as a genetic blueprint, researchers have also worked the biopolymer into their plans for building biosensors, semiconductors, and other devices. By programming the nucleotide sequence of each DNA molecule, scientists can control the bonding between strands and contort the polymers into seemingly arbitrary shapes. But building DNA crystals thicker than a few nanometers has proven to be a challenge. Researchers led by Yonggang Ke, Luvena L. Ong, Wei Sun, and Peng Yin of Harvard University have now developed a modular process for constructing crystals that can extend for micrometers in two directions and up to 80 nm in the third direction (Nat. Chem. 2014, DOI: 10.1038/nchem.2083). Working with their “DNA bricks,” the researchers are able to build cubic structures that serve as unit cells that self-assemble into larger lattices. By programming vacancies into these cuboids, the team creates crystals with more complex three-dimensional structures, such as channels and pores.