| 摘要 |
<p>Modular unit (A) characterized by a substantally circular base, and a shape obtained by the combination of a substantially cylindrical body and a substantially frustum body, cohaxial one to the other, the latter being placed on a base of the cylindrical body, the external surface of said modular unit being characterized by the presence of notches (5), (7) and projections (4), (6), (6'), symmetrically and alternately placed so that at least one of said projections of a first element be housed in a corresponding notch of a second unit and the two units mortise one another. <IMAGE></p> |
