Construction set for building structures

The present invention relates to construction sets for children and for commercial and other uses as well, enabling the building of both two and three-dimensional structures of various dimensions and geometry, preferably using elements made of foam, plastic and the like to provide flexible and safe structures. A novel construction set particularly useful for children safely to assemble and use two-and three-dimensional structures of a wide range of sizes and shapes with flexible foam-like tubes or rods detachable to male or female elements carried by foam-like connectors, and preferably of hexaoctahedral or spherical contour, and with such novel geometric design also useful with other construction materials for other uses as well.