Abstract: Modular systems for the construction of three-dimensional structures are disclosed. A system includes a first panel, a second panel, and a fixing member. The first panel includes a first edge and a first attachment member. The second panel includes a second edge and a second attachment member. The second edge is configured to mate with the first edge of the first panel. This mating forms a hinge that couples the first and the second panels and enables a relative rotation about a rotation axis through the hinge. The relative rotation defines a relative angle between the first and the second panels. The fixing member is configured to couple to each of the first and the second attachment members when the relative angle between the first and the second panels is equivalent to a first angle, fixing the relative angle at the first angle and forming the structure.