Abstract: A geometric construction set for building a stable cubic structure, comprising a plurality of like-dimensioned connecting members, spherical magnetically sensitive bodies and anchoring members. Each connecting member has radial symmetry along its axis of elongation and includes permanent magnets at its first and second ends. The anchoring members have three mutually perpendicular and substantially semi-cylindrical arms, a partial spherical cavity at the intersection of the three arms, and a cavity within each of the arms created by its semi-cylindrical shape. The partial spherical cavity is adapted to receive the spherical magnetically sensitive bodies. The cavities in the arms are adapted to securely receive either the first end or the second end of the connecting members. After securely received in the arms, the first or second ends of the connecting member with the permanent magnets are magnetically coupled with the spherical magnetically sensitive bodies.