A foldable structure comprised of hinged panel segments is provided. These segments are comprised of a first panel pair comprised of a first and second polygonal panel, and a second panel pair comprised of a third and fourth polygonal panel. Segments are bounded by a first boundary plane defined by two sides of the first panel pair, and a second boundary plane defined by two sides of the second panel pair, Measurement of a boundary angle may be taken normal to the intersection of the first and second boundary planes. As the segment is continuously folded between a first position and a second position, said boundary angle remains substantially constant during folding.