Nickel salts can induce flexibility in DNA structures and were used in high quantity (0.2 -1 M) to prepare the mica surface for AFM imaging (Supplementary Figs. 30-31). Bending was also observed in TEM imaging, suggesting that triplex origami bundles are inherently somewhat flexible. Regardless, the five-fold bundle proved to be a robust design that folded in low-salt conditions (5 mM Mg 2+ ) and remained stable in a neutral buffer. The packing of up to three neighbours per folded segment is required to build scalable three-dimensional structures using a honeycomb-lattice. This is demonstrated in the third design, which is a twelve-fold honeycomb-lattice bundle (Fig. ). It is assembled from an 8523 bp scaffold and 104 TFO staples, the routing of which is mostly similar to the five-fold hexagonal bundle except that it halves the crossover density between certain folds to conserve staple length.