the hypotenuse of a base face tl and said eighth module th is joined to said first module ta along the corner t 4 corresponding to one of the shorter sides of a base face tl the new seating system can thus be put together in multiple different configurations simply by rotating a module ti in relation to the adjacent one around the axis tx lying on the corresponding connection corner t 4 and thus creating seating systems having various shapes the new seating system can be put together in such a way as to create very compact configurations parallelepiped in shape as shown in fig9 10 11 12 14 whose plan size corresponds to the surface area of a square fig1 whose surface area equals the sum of the surface areas of two triangular base faces tl of the modules ti 5 or whose plan size corresponds to the surface area of four squares placed side by side fig1 or whose plan size corresponds to the surface area of two squares placed side by side fig9 10 or whose plan size corresponds to the surface area of a square fig1 whose surface area equals the sum of the surface areas of four triangular base faces tl of the modules ti said compact configurations create seating systems with one or more seats o that is substantially horizontal supporting surfaces but without backs v or armrests b the new seating system can also be put together in such a way as to form configurations that as a whole are prismatic in shape with triangular cross section fig1 or cross section consisting of two triangles arranged specularly fig1 17 18 said.