Plio/Rayf/Rivf :

In this family the center angle and the edge angle are projected on the frontal plane. This subdivision makes it possible to obtain completely closed forms. They have three equivalent, vertical, symmetrical planes and one horizontal one. When the form is cut on one of its symmetrical plane, we obtain two types of forms which can be put on a plane. This gives linear continuity to the support system and enables shared distribution of the strain to a large number of points.