Strands of DNA can be folded into flat structures as elaborate as maps of the Americas. The DNA origami technique developed by California Institute of Technology computer scientist Paul Rothemund takes a long DNA and folds it repeatedly like a piece of string to create any desired shape, much like drawing a picture using a single line. Short DNAs are added to hold each fold in place. The results, revealed in the March 16 Nature, are origami forms up to roughly 100 nanometers wide made of about 200 pixels, in which each pixel is a short nucleotide chain. DNA's propensity for spontaneously lining up with matching sequences means these shapes will assemble themselves auto matically if the molecules are sequenced prop erly. Designing structures takes about a day, using a computer program simple enough for a high school chemistry experiment. Scientists could create devices with such origami by attaching electronics or enzymes, and experiments have begun creating three-dimensional structures.