Engineers have found a new and unexpected use for the code of life—as a commonplace building material that can be used to fashion precise 3D structures, ranging from miniature smiley faces to cubes. Peng Yin, HMS assistant professor of systems biology and core faculty member of the Wyss Institute for Biologically Inspired Engineering, is one of the leaders of the work. George Church, Robert Winthrop Professor of Genetics at HMS and founding core faculty member at the Wyss, is also quoted.