If you’ve ever tried to fold an origami butterfly and watched helplessly as your hands mangled it into a sickly pterodactyl, you know folding paper can be tricky. A new algorithm could help. Once you’ve created a polyhedral design on your computer, say a bunny, the “Origamizer” maps its flat faces—triangles and such—onto a piece of paper. It then figures out how to fold all of the excess paper out of the way so the faces come together in just the right way. One of the researchers behind the Origamizer had designed a previous origami algorithm, but it “cheated” by requiring that the paper first be cut or folded into a long strip, creating lots of seams in the final object. The new method has the ability to render shapes “watertight”: You can make the edge of the paper become the edge of a 3D shape—say the rim of a bowl—and there will be no seams anywhere else. The researches plan to present their work at the 33rd International Symposium on Computational Geometry in July. The above bunny was folded in 2011 from a sheet of steel (with holes cut in it) according to an earlier version of the Origamizer.