A system of interconnectable construction elements created from molded plastic, wood or metal, and which include four basic construction elements, wherein a first and second construction element include a hemispherical segment and a planar connecting segment and complementary male and female connectors, and third and fourth construction elements that include a hemispherical segment with complementary male and female connectors, wherein the first and second construction elements can be coupled together, the third and fourth construction elements can be coupled together, or one of the first and second construction elements can be coupled to a complementary one of the third or fourth construction elements.