But using tiny loops of DNA as “bricks”, Harvard (of course) scientists have developed a Lego-like set of nucleic acid building blocks. The sequences in each loop only stick to certain neighbors in certain orientations, just like real Legos. Those rules are defined by all the standard base-pairing rules that you learned in biology class. You can see some of the shapes that they’ve developed above.
Ed Yong digs deep into the blocks at Not Exactly Rocket Science.