 Foreshadowing work on the general fold-and-cut theorem, he writes that "more complicated designs present formidable problems".The first proof of the fold-and-cut theorem, solving the problem, was published in 1999 by Erik Demaine, Martin Demaine, and Anna Lubiw.There are two general methods known for solving instances of the fold-and-cut problem, based on straight skeletons and on circle packing respectively.