Interlockable element for structure assembly set

A structure assembly set comprising a first interlockable element and a second interlockable element, each of the first and second elements including an at least partially planar body and a connector edge having associated therewith a first A-type and B-type connector pair disposed about a first axis of rotation and a second A-type and B-type connector pair disposed about a second axis of rotation;

• wherein for each said connector edge the first and second axes of rotation are disposed on opposing sides of a generally rectangular quadrilateral of a specified dimension, with each of one pair of diagonally opposite vertices of the quadrilateral situated internally to each of said A-type connectors and each of the other pair of diagonally opposite vertices of the quadrilateral situated internally to each of said B-type connectors;
• wherein the quadrilateral is generally disposed in a plane that is generally perpendicular to the plane of said at least partially planar body of the respective interlockable element;
• and
• wherein said connector pairs of the first element match for rotational interlocking engagement with said connector pairs of the second element.