An element of an erection set has a body provided with a rigid projection and a flexible plate spaced from one another so as to form a gap therebetween such that a width of the gap between ends of the projection and the plate is greater than a width of the gap between tops of the rigid projection and the flexible plate is greater than a width of the gap between bottoms of the rigid projection and the flexible plate, and the plates of at least two of such elements are engageable with one another and displaceable relative to one another due to equalization of stresses formed by deformation of the flexible plate during displacement of the flexible plates over the rigid projections of two elements relative to one another and bending of the flexible plates over a surface of the rigid projections during connection of two elements with one another.