Abstract:
A building structure formed of at least one saddle element defining a plurality of edges and rigid structural elements extending along the edges of each of the at least one saddle element, the rigid structural elements being characterized in that they lie along diagonals of sides of a rectangular parallelepiped forming part of a modular array of rectangular parallelepiped geometrical structures underlying the at least one saddle element and may include octet-like beams or octet-like trusses Multiple saddle elements, either of a similar type or of varying types, may be combined into a wide variety of possible structures Saddle elements can be a tensioned membrane element or any other suitable material.

Description:
FIELD OF THE INVENTION 
   The present invention relates to building structures and methodologies generally and more particularly to building structures and methodologies incorporating a plurality of saddle elements 
   BACKGROUND OF THE INVENTION 
   A great variety of building structures are known in the prior art patent literature The following U.S. Patents and texts are believed to be representative of the current state of the art 
   U.S. Pat. Nos. 2,986,241, 3,600,825, 3,925,941; 3,931,697, 4,092,992; 4,584,800; 4,620,998, 4,651,479; 4,869,041; 5,036,635, 5,155,951 and 5,899,028 
   Vachman, A et al, Infinite Polyhedra, 1974; 
   Pearce, Structures in Nature is a Strategy for Design, 1978; 
   Korren, A, Periodic 2 Manifolds Surfaces which divide the Space into two identical Subspaces, 1993 
   Burt, M, The Periodic Table of the Polihedral Universe, 1996, 
   Gabriel, J F, Beyond the Cube, 1997 
   SUMMARY OF THE INVENTION 
   The present invention seeks to provide improved building structures and methodologies employing saddle elements One example, but not the only example, of a saddle element is a hypar Another example of a saddle element is commonly termed a “minimal surface” The saddle element is preferably formed of a flexible material, but alternatively may be rigid or semi-rigid. The saddle element may be formed of any suitable material or combination of materials and may be constructed in any suitable manner 
   The present invention provides building structures formed of at least one saddle element defining a plurality of edges and rigid structural elements extending along the edges of each of the at least one saddle element, the rigid structural elements being, characterized in that they lie along diagonals of sides of a rectangular parallelepiped forming part of a modular array of rectangular parallelepiped geometrical structures underlying the at least one saddle element and comprise octet-like trusses. 
   The present invention also provides a building structure formed of a plurality of saddle elements and rigid structural elements extending along the edges of each of the plurality of saddle elements, the rigid structural elements being characterized in that they lie along diagonals of sides of a rectangular parallelepiped forming part of a modular array of rectangular parallelepiped geometrical structures underlying the plurality of saddle elements 
   Preferably, the rigid structural elements are further characterized in that they lie along diagonals which form part of an octet structure 
   In accordance with a preferred embodiment of the present invention, the at least one saddle element includes at least two saddle elements of different types 
   Preferably, the rigid structural elements comprise octet trusses 
   An octet geometry is described in U.S. Pat. No. 2,986,241 of Buckminster Fuller and is here defined with reference to a cubic grid as follows: 
   Take eight adjacent imaginary cubes which all have a single common corner Twelve diagonals extend outwardly from the single common corner, each such diagonal extending along a common wall of a pair of adjacent cubes from the single common corner to each common corner at the junction of the pair of adjacent cubes. The angle between each of the twelve diagonals and an adjacent diagonal lying along the same plane of a surface of a cube is 90 degrees, while the angle between each of the twelve diagonals and an adjacent diagonal lying in a plane of a surface of a cube perpendicular thereto is 60 degrees. 
   An octet geometry is based on diagonals having the geometrical relationship described above and may have multiple single common corners. 
   An octet geometry includes octahedrons and tetrahedrons, wherein each surface of each octahedron is coextensive with a surface of a tetrahedron and each surface of each tetrahedron is coextensive with a surface of an octahedron Each diagonal is common to two octahedrons and to two tetrahedrons. 
   An octet structure is a structure constructed in accordance with an octet geometry 
   An octet-like structure is a generalization of an octet structure to a wherein the cubes referred to hereinabove are replaced by any rectangular parallelepiped forming part of a modular array of rectangular parallelepiped geometrical structures 
   Thus, an octet-like truss is a truss formed of diagonals which define an octet-like structure 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which 
       FIG. 1  is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention, 
       FIGS. 2A &amp; 2B  are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 1 , 
       FIG. 3  is a simplified illustration of a building structure, constructed and operative in accordance with another preferred embodiment of the present invention; 
       FIGS. 4A &amp; 4B  are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 3 , 
       FIG. 5  is a simplified illustration of a building structure, constructed and operative in accordance with yet another preferred embodiment of the present invention; 
       FIGS. 6A ,  6 B and  6 C are simplified illustrations of three junctions of rigid structural elements in the embodiment of  FIG. 5 ; 
       FIG. 7  is a simplified illustration of a building structure, constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIGS. 8A ,  8 B and  8 C are simplified illustrations of three junctions of rigid structural elements in the embodiment of  FIG. 7 ; 
       FIG. 9  is a simplified illustration of a building structure, constructed and operative in accordance with another preferred embodiment of the present invention; 
       FIGS. 10A and 10B  are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 9 , 
       FIG. 11  is a simplified illustration of a building structure, constructed and operative in accordance with yet another preferred embodiment of the present invention, 
       FIGS. 12A and 12B  are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 11 , 
       FIG. 13  is a simplified illustration of a building structure, constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIG. 14  is a simplified illustration of a junction of rigid structural elements in the embodiment of  FIG. 13 , 
       FIG. 15  is a simplified illustration of a building structure, constructed and operative in accordance with yet another preferred embodiment of the present invention; 
       FIG. 16  is a simplified illustration of a junction of rigid structural elements in the embodiment of  FIG. 15 ; 
       FIG. 17  is a simplified illustration of a building structure, constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIG. 18  is a simplified illustration of a junction of rigid structural elements in the embodiment of  FIG. 17 , 
       FIG. 19  is a simplified illustration of a building structure, constructed and operative in accordance with yet another preferred embodiment of the present invention, 
       FIG. 20  is a simplified illustration of a junction of rigid structural elements in the embodiment of  FIG. 19 , 
       FIG. 21  is a simplified illustration of a building structure, constructed and operative in accordance with a further preferred embodiment of the present invention; 
       FIGS. 22A &amp; 22B  are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 21 , 
       FIG. 23  is a simplified illustration of a building structure, constructed and operative in accordance with another preferred embodiment of the present invention, 
       FIGS. 24A &amp; 24B  are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 23 , 
       FIG. 25  is a simplified illustration of a building structure, constructed and operative in accordance with a still further preferred embodiment of the present invention, 
       FIGS. 26A &amp; 26B  are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 25 , 
       FIG. 27  is a simplified illustration of a building structure, constructed and operative in accordance with another preferred embodiment of the present invention; 
       FIGS. 28A &amp; 28B  are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 27 , 
       FIGS. 29A ,  29 B,  29 C and  29 D are simplified illustrations of four variations of rigid structural elements useful in various embodiments of the present invention, 
       FIGS. 30A ,  30 B,  30 C and  30 D are simplified illustrations of an additional four variations of rigid structural elements useful in various embodiments of the present invention, 
       FIGS. 31A and 31B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with another preferred embodiment of the present invention, 
       FIGS. 32A and 32B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention, 
       FIGS. 33A and 33B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIGS. 34A and 34B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with another preferred embodiment of the present invention; 
       FIGS. 35A and 35B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention, 
       FIGS. 36A and 36B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIGS. 37A and 37B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with another preferred embodiment of the present invention, 
       FIGS. 38A and 38B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention; 
       FIGS. 39A and 39B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIGS. 40A and 40B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with another preferred embodiment of the present invention, 
       FIGS. 41A and 41B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention, 
       FIGS. 42A and 42B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIGS. 43A and 43B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with another preferred embodiment of the present invention, 
       FIGS. 44A and 44B  are respective isometric and perspective illustrations of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention, 
       FIG. 45  is a roof plan view illustration of a structure constructed and operative in accordance with another preferred embodiment of the present invention; 
       FIGS. 46A and 46B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 45 , 
       FIGS. 47A and 47B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 45 ; 
       FIG. 48  is a roof plan view illustration of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention; 
       FIGS. 49A and 49B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 48 ; 
       FIGS. 50A and 50B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 48 , 
       FIG. 51  is a roof plan view illustration of a structure constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIGS. 52A and 52B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 51 , 
       FIGS. 53A and 53B  which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 51 , 
       FIG. 54  is a roof plan view illustration of a structure constructed and operative in accordance with another preferred embodiment of the present invention, 
       FIGS. 55A and 55B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 54 , 
       FIGS. 56A and 56B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 54 ; 
       FIG. 57  is a roof plan view illustration of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention, 
       FIGS. 58A and 58B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 57 , 
       FIGS. 59A and 59B  which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 57 ; 
       FIG. 60  is a roof plan view illustration of a structure constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIGS. 61A and 61B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 60 , 
       FIGS. 62A and 62B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 60 , 
       FIG. 63  is a roof plan view illustration of a structure constructed and operative in accordance with another preferred embodiment of the present invention, 
       FIGS. 64A and 64B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 63 , 
       FIGS. 65A and 65B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 63 , 
       FIG. 66  is a roof plan view illustration of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention; 
       FIGS. 67A and 67B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 66 , 
       FIGS. 68A and 68B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 66 , 
       FIG. 69  is a roof plan view illustration of a structure constructed and operative in accordance with still another preferred embodiment of the present invention. 
       FIGS. 70A and 70B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 69 , 
       FIGS. 71A and 71B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 69 ; 
       FIG. 72  is a roof plan view illustration of a structure constructed and operative in accordance with another preferred embodiment of the present invention; 
       FIGS. 73A and 73B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 72 , 
       FIGS. 74A and 74B  which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 72 , 
       FIGS. 75A and 75B  illustrate an example of an integrated structure employing structural elements of the types described hereinabove together with a conventional three-dimensional tensioned cable system for providing enhanced overall constructional efficiency in accordance with another preferred embodiment of the present invention, 
       FIGS. 76A &amp; 76B  illustrate another example of an integrated structure employing structural elements of the types described hereinabove together with a conventional three-dimensional tensioned cable system for providing enhanced overall constructional efficiency in accordance with another preferred embodiment of the present invention, 
       FIG. 77  is a roof plan view illustration of the structure of  FIGS. 76A &amp; 76B , 
       FIGS. 78A and 78B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 77 ; 
       FIGS. 79A and 79B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 77 ; 
       FIGS. 80A and 80B  are, respectively, a roof plan view and an isometric illustration of an alternative realization of the structure of  FIGS. 76A-79B , 
       FIG. 81  is a roof plan view illustration of a structure constructed and operative in accordance with another preferred embodiment of the present invention; 
       FIGS. 82A and 82B  are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 81 , 
       FIGS. 83A and 83B  are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 81 , 
       FIG. 84  is a simplified illustration of a structure constructed and operative in accordance with yet another preferred embodiment of the present invention; 
       FIG. 85  illustrates a structure similar to that shown in  FIG. 84 ; 
       FIG. 86  is a roof plan view illustration of a structure constructed and operative in accordance with still another preferred embodiment of the present invention, 
       FIGS. 87A ,  87 B and  87 C are three elevation view illustrations of one embodiment of the structure of  FIG. 86 , 
       FIG. 88  is an isometric illustration of the embodiment of  FIGS. 87A-87C , 
       FIGS. 89A ,  89 B and  89 C are three perspective illustrations of the embodiment of  FIGS. 87A-88 , 
       FIGS. 90A ,  90 B and  90 C are three elevation view illustrations of another embodiment of the structure of  FIG. 86 ; 
       FIG. 91  is an isometric illustration of the embodiment of  FIGS. 90A-90C , and 
       FIGS. 92A ,  92 B and  92 C are three perspective illustrations of the of embodiment of  FIGS. 90A-91   
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Reference is now made to  FIG. 1 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention, including four type A saddle elements, as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of cubes The rigid structural elements define part of an octet structure 
   The saddle elements are preferably formed of a flexible material, such as a tensioned membrane, but alternatively may be rigid or semi-rigid The saddle elements may be formed of any suitable material or combination of materials and may be constructed in any suitable manner. 
   As seen in  FIG. 1 , the building structure comprises type A saddle elements  10 ,  12 ,  14  and  16  in two different orientations A single type A saddle element surrounded by rigid structural elements in the form of beams arranged to define part of an octet structure is shown in window  20  and a single type A saddle element surrounded by rigid structural elements in the form of trusses arranged to define part of an octet structure is shown in window  22  The use of trusses, particularly octet trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  20  and  22   
   The type A saddle elements in this embodiment are characterized in that they define four 60 degree junctions It is appreciated that type A saddle elements are each circumscribed by a single cube, whose side dimensions X, Y &amp; Z are all equal.  FIG. 1  illustrates a type A saddle element which is circumscribed by a rectangular parallelepiped, designated by reference numeral  24 , whose side dimensions X, Y &amp; Z are all equal, thus defining a cube. 
   Type A saddle elements are characterized in that they have four edges, designated in  FIG. 1  by reference numerals  26 ,  28 ,  30  and  32 , each defined by a diagonal extending, along a side surface of the rectangular parallelepiped The side surfaces whose diagonals define edges  26 ,  28 ,  30  and  32  are respectively designated by reference numerals  36 ,  38 ,  40  and  42  Four junctions, designated by reference numerals  44 ,  46 ,  48  and  50 , are defined by the four edges, each junction being located at the meeting of the ends of two adjacent edges Two parallel side surfaces of the cube, here designated by reference numerals  52  and  54 , do not have edges defined along the diagonals thereof 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  20  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet trusses, linear combinations of octahedrons and tetrahedrons, as shown in window  22  Rigid structural elements of this type are known, for example in U.S. Pat. No. 4,869,041, for other applications 
   Reference is now made to  FIGS. 2A &amp; 2B , which are simplified illustrations of two junctions of rigid structural elements in the embodiment of FIG.  1 .  FIG. 2A  shows the junction  60  of four rigid structural elements, designated here and in  FIG. 1  by reference numerals  62 ,  64 ,  66  and  68 . It is seen that the junction of rigid structural elements  62 ,  64 ,  66  and  68  defines an octahedron  70 , which is common to all four elements 
     FIG. 2B  shows the junction  80  of three rigid structural elements, designated here and in  FIG. 1  by reference numerals  82 ,  84  and  86  It is seen that the junction of rigid structural elements  82 ,  84  and  86  is also an octahedron  88 , which is common to all three elements 
   Reference is now made to  FIG. 3 , which is a simplified illustration of a building structure, constructed and operative in accordance with another preferred embodiment of the present invention including four type A saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of non-cubic rectangular parallelepipeds. The rigid structural elements define part of an octet-like structure 
   As seen in  FIG. 3 , the building structure comprises type A saddle elements  110 ,  112 ,  114  and  116  in two different orientations. A single type A saddle element surrounded by rigid structural elements in the form of beams is shown in window  120  and a single type A saddle element surrounded by rigid structural elements in the form of trusses is shown in window  122  The use of trusses, particularly octet-like trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  120  and  122   
   The type A saddle elements in this embodiment are characterized in that they define four junctions which are not necessarily identical It is appreciated that type A saddle elements are each circumscribed by a single rectangular parallelepiped, whose side dimensions X, Y &amp; Z may be, but need not be, equal  FIG. 3  illustrates a type A saddle element which is circumscribed by a rectangular parallelepiped, designated by reference numeral  124 , whose side dimensions X, Y &amp; Z are not all equal 
   Type A saddle elements are characterized in that they have four edges, designated in  FIG. 3  by reference numerals  126 ,  128 ,  130  and  132 , each defined by a diagonal extending, along a side surface of the rectangular parallelepiped. The side surfaces whose diagonals define edges  126 ,  128 ,  130  and  132  are respectively designated by reference numerals  136 ,  138 ,  140  and  142  Four junctions, designated by reference numerals  144 ,  146 ,  148  and  150 , are defined by the four edges, each junction being located at the meeting of the ends of two adjacent edges Two parallel side surfaces of the rectangular parallelepiped, here designated by reference numerals  152  and  154 , do not have edges defined along the diagonals thereof 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  120  According to a preferred embodiments of the present invention, rigid structural elements are constructed as trusses, most preferably as octet-like trusses linear combinations of octahedron-like structures and tetrahedron-like structures, as shown in window  122   
   Reference is now made to  FIGS. 4A &amp; 4B , which are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 3   FIG. 4A  shows the junction  160  of four rigid structural elements, designated here and in  FIG. 3  by reference numerals  162 ,  164 ,  166  and  168 . It is seen that the junction of rigid structural elements  162 ,  164 ,  166  and  168  defines an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  170 , is common to all four elements 
     FIG. 4B  shows a junction  180  of three rigid structural elements designated here and in  FIG. 3  by reference numerals  182 ,  184  and  186  It is seen that the junction of rigid structural elements  182 ,  184  and  186  is also an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  190 , is common to all three elements 
   Reference is now made to  FIG. 5 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including five type B saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of cubes The rigid structural elements define part of an octet structure. 
   As seen in  FIG. 5 , the building structure comprises type B saddle elements  208 ,  210 ,  212 ,  214  and  216  in five different orientations A single type B saddle element surrounded by rigid structural elements in the form of beams is shown in window  220  and a single type B saddle element surrounded by rigid structural elements in the form of trusses is shown in window  222  The use of trusses, particularly octet trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  220  and  222   
   The type B saddle elements in this embodiment are characterized in that they define two 60 degree junctions and two 90 degree junctions. It is appreciated that type B saddle elements are each circumscribed by a pair of adjacent cubes, whose side dimensions X, Y &amp; Z are all equal  FIG. 5  illustrates a type B saddle element which is circumscribed by a pair of adjacent rectangular parallelepipeds having a common side surface, designated by reference numerals  224  and  225 , whose side dimensions X, Y &amp; Z are all equal, thus defining a pair of adjacent cubes 
   Type B saddle elements are characterized in that they have four edges, designated in  FIG. 5  by reference numerals  226 ,  228 ,  230  and  232 , each defined by a diagonal extending along a side surface of a rectangular parallelepiped. The side surfaces whose diagonals define edges  226 ,  228 ,  230  and  232  are respectively designated by reference numerals  236 ,  238 ,  240  and  242  Surfaces  236  and  238  lie in the same plane, which extends perpendicularly to the plane of surfaces  240  and  242 . Four junctions, designated by reference numerals  244 ,  246 ,  248  and  250 , are defined by the four edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  220  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet trusses, linear combinations of octahedrons and tetrahedrons, as shown in window  222  Rigid structural elements of this type are known, for example in U.S. Pat. No. 4,869,041, for other applications. 
   Reference is now made to  FIGS. 6A ,  6 B &amp;  6 C, which are simplified illustrations of three junctions of rigid structural elements in the embodiment of  FIG. 5   FIG. 6  A shows the junction  260  of three rigid structural elements, designated here and in  FIG. 5  by reference numerals  262 ,  264  and  266  It is seen that the junction of rigid structural elements  262 ,  264  and  266  defines an octahedron  270 , which is common to all three elements 
     FIG. 6B  shows the junction  280  of two rigid structural elements, designated here and in  FIG. 5  by reference numerals  282  and  284 . It is seen that the junction of rigid structural elements  282  and  284  is also an octahedron  288 , which is common to both elements 
     FIG. 6C  shows the intersection  290  of three rigid structural elements, designated here and in  FIG. 5  by reference numerals  292 ,  294  and  296  It is seen that the intersection of rigid structural elements  292 ,  294  and  296  is also an octahedron  298 , which is common to all three elements 
   Reference is now made to  FIG. 7 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including five type B saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of non-cubic rectangular parallelepipeds The rigid structural elements define part of an octet-like structure 
   As seen in  FIG. 7 , the building structure comprises five type B saddle elements  308 ,  310 ,  312 ,  314  and  316  in five different orientations A single type B saddle element surrounded by rigid structural elements in the form of beams is shown in window  320  and a single type B saddle element surrounded by rigid structural elements in the form of trusses is shown in window  322  The use of trusses, particularly octet-like trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  320  and  322   
   The type B saddle elements in this embodiment are each circumscribed by a pair of adjacent rectangular parallelepipeds having a common side surface, whose side dimensions X, Y &amp; Z are not all equal. The pair of adjacent rectangular parallelepipeds having a common side surface are designated by reference numerals  324  and  325   
   Type B saddle elements are characterized in that they each have four edges, designated in  FIG. 7  by reference numerals  326 ,  328 ,  330  and  332 , each defined by a diagonal extending, along a side surface of a rectangular parallelepiped The side surfaces whose diagonals define edges  326 ,  328 ,  330  and  332  are respectively designated by reference numerals  336 ,  338 ,  340  and  342  Surfaces  336  and  338  lie in the same plane, which extends perpendicularly to the plane of surfaces  340  and  342 . Four junctions, designated by reference numerals  344 ,  346 ,  348  and  350 , are defined by the four edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  320  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet-like trusses, linear combinations of octahedron-like structures and tetrahedron-like structures, as shown in window  322   
   Reference is now made to  FIGS. 8A ,  8 B &amp;  8 C, which are simplified illustrations of three junctions of rigid structural elements in the embodiment of FIG.  7 .  FIG. 8A  shows the junction  360  of three rigid structural elements, designated here and in  FIG. 7  by reference numerals  362 ,  364  and  366  It is seen that the junction of rigid structural elements  362 ,  364  and  366  defines an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  370 , is common to all three elements 
     FIG. 8B  shows the junction  380  of two rigid structural elements, designated here and in  FIG. 7  by reference numerals  382  and  384  It is seen that the junction of rigid structural elements  382  and  384  is also an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  388 , is common to both elements. 
     FIG. 8C  shows the intersection  390  of three rigid structural elements, designated here and in  FIG. 7  by reference numerals  392 ,  394  and  396  It is seen that the intersection of rigid structural elements  392   394  &amp;  396  is also an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  398 , is common to all three elements 
   Reference is now made to  FIG. 9 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including three type C saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of cubes The rigid structural elements define part of an octet structure 
   As seen in  FIG. 9 , the building structure comprises type C saddle elements  410 ,  412  and  414  in three different orientations A single type C saddle element surrounded by rigid structural elements in the form of beams is shown in window  420  and a single type C saddle element surrounded by rigid structural elements in the form of trusses is shown in window  422  The use of trusses, particularly octet trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  420  and  422   
   The type C saddle elements in this embodiment are characterized in that they define four 60 degree junctions and two 90 degree junctions It is appreciated that type C saddle elements are each circumscribed by a pair of adjacent cubes having a common face, whose side dimensions X, Y &amp; Z are all equal  FIG. 9  illustrates a type C saddle element which is circumscribed by a pair of adjacent rectangular parallelepipeds having a common side surface, designated by reference numerals  424  and  425 , whose side dimensions X, Y &amp; Z are all equal, thus defining a pair of adjacent cubes. 
   Type C saddle elements are characterized in that they have six edges, designated in  FIG. 9  by reference numerals  426 ,  427 ,  428 ,  429 ,  430  and  431 , each defined by a diagonal extending along a side surface of a rectangular parallelepiped. The side surfaces whose diagonals define edges  426 ,  427 ,  428 ,  429 ,  430  and  431  are respectively designated by reference numerals  436 ,  437 ,  438 ,  439 ,  440  and  441  Surfaces  436  and  437  lie in the same plane, which extends parallel to and spaced from the plane of surfaces  439  and  440  Surfaces  436 ,  437 ,  439  and  440  are perpendicular to planes  438  and  441 , which are mutually parallel and spaced from each other Six junctions, designated by reference numerals  444 ,  445 ,  446 ,  447 ,  448  and  449 , are defined by the six edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  420  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet trusses, linear combinations of octahedrons and tetrahedrons as shown in window  422  Rigid structural elements of this type are known, for example in U.S. Pat. No. 4,869,041, for other applications 
   Reference is now made to  FIGS. 10A and 10B , which are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 9   FIG. 10A  shows the junction  460  of three rigid structural elements, designated here and in  FIG. 9  by reference numerals  462 ,  464  and  466  It is seen that the junction of rigid structural elements  462 ,  464  and  466  defines an octahedron  470 , which is common to all three elements 
     FIG. 10B  shows the junction  480  of two rigid structural elements, designated here and in  FIG. 9  by reference numerals  482  and  484  It is seen that the junction of rigid structural elements  482  and  484  is also an octahedron  488 , which is common to both elements 
   Reference is now made to  FIG. 11 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including three type C saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of non-cubic rectangular parallelepipeds. The rigid structural elements define part of an octet-like structure 
   As seen in  FIG. 11 , the building structure comprises type C saddle elements  510 ,  512  and  514  in three different orientations A single type B saddle element surrounded by rigid structural elements in the form of beams is shown in window  520  and a single type B saddle element surrounded by rigid structural elements in the form of trusses is shown in window  522  The use of trusses, particularly octet-like trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  520  and  522   
   The type C saddle elements in this embodiment are each circumscribed by a pair of adjacent non-cubic rectangular parallelepipeds having a common side surface, whose side dimensions X, Y &amp; Z are not all equal. The pair of adjacent rectangular parallelepipeds having a common side surface are designated by reference numerals  524  and  525   
   Type C saddle elements are characterized in that they have six edges, designated in  FIG. 11  by reference numerals  526 ,  527 ,  528 ,  529 ,  530  and  531 , each defined by a diagonal extending along a side surface of a rectangular parallelepiped The side surfaces whose diagonals define edges  526 ,  527 ,  528 ,  529 ,  530  and  431  are respectively designated by reference numerals  536 ,  537 ,  538 ,  539 ,  540  and  541  Surfaces  536  and  537  lie in the same plane, which extends parallel to and spaced from the plane of surfaces  539  and  540  Surfaces  536 ,  537 ,  539  and  540  are perpendicular to planes  538  and  541 , which are mutually parallel and spaced from each other. Six junctions, designated by reference numerals  544 ,  545 ,  546 ,  547 ,  548  and  549 , are defined by the six edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  520  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet-like trusses, linear combinations of octahedron-like structures and tetrahedron-like structures, as shown in window  522   
   Reference is now made to  FIGS. 12A &amp; 12B , which are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 11   FIG. 12A  shows the junction  560  of three rigid structural elements, designated here and in  FIG. 11  by reference numerals  562 ,  564  and  566  It is seen that the junction of rigid structural elements  562 ,  564  and  566  defines an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  570 , is common to all three elements 
     FIG. 12B  shows the junction  580  of two rigid structural elements, designated here and in  FIG. 11  by reference numerals  582  and  584 . It is seen that the intersection of rigid structural elements  582  and  584  is also an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  586  is common to both elements 
   Reference is now made to  FIG. 13 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including three type D saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of cubes The rigid structural elements define part of an octet structure. 
   As seen in  FIG. 13 , the building structure comprises type D saddle elements  610 ,  612  and  614  in two different orientations A single type D saddle element surrounded by rigid structural elements in the form of beams is shown in window  620  and a single type D saddle element surrounded by rigid structural elements in the form of trusses is shown in window  622  The use of trusses, particularly octet trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  620  and  622 . 
   The type D saddle elements in this embodiment are characterized in that they define four 60 degree junctions and four 90 degree junctions. It is appreciated that type D saddle elements are each circumscribed by four adjacent cubes having a common edge, whose side dimensions X, Y &amp; Z are all equal.  FIG. 13  illustrates a type D saddle element which is circumscribed by four adjacent rectangular parallelepipeds having a common edge, designated by reference numeral  624 , whose side dimensions X, Y &amp; Z are all equal, thus defining four adjacent cubes 
   Type D saddle elements are characterized in that they have eight edges, designated in  FIG. 13 , by reference numerals  625 ,  626 ,  627 ,  628 ,  629 ,  630 ,  631  and  632  each defined by a diagonal extending along a side surface of a rectangular parallelepiped The side surfaces whose diagonals define edges  625 ,  626 ,  627 ,  628 ,  629 ,  630 ,  631  and  632  are respectively designated by reference numerals  635 ,  636 ,  637 ,  638 ,  639 ,  640 ,  641  and  642  Surfaces  635  and  636  lie in the same plane, which extends parallel to and spaced from the plane of surfaces  639  and  640 . Surfaces  637  and  638  lie in a common plane, which is perpendicular to planes  635 ,  636 ,  639  and  640  Surfaces  637  and  638  lie in parallel spaced relationship with surfaces  641  and  642 , which both lie in a common plane Eight junctions, designated by reference numerals  643 ,  644 ,  645 ,  646 ,  647 ,  648 ,  649  and  650  are defined by the eight edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  620  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet trusses, linear combinations of octahedrons and tetrahedrons, as shown in window  622  Rigid structural elements of this type are known, for example in U.S. Pat. No. 4,869,041, for other applications. 
   Reference is now made to  FIG. 14 , which is a simplified illustration of a junction of rigid structural elements in the embodiment of  FIG. 13   FIG. 14  shows the junction  660  of three rigid structural elements, designated by reference numerals  662 ,  664  and  666  It is seen that the junction of rigid structural elements  662 ,  664  and  666  defines an octahedron  670 , which is common to all three elements 
   Reference is now made to  FIG. 15 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including three type D saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of non-cubic rectangular parallelepipeds The rigid structural elements define part of an octet-like structure 
   As seen in  FIG. 15 , the building structure comprises type D saddle elements  710 ,  712  and  714  in two different orientations A single type D saddle element surrounded by rigid structural elements in the form of beams is shown in window  720  and a single type D saddle element surrounded by rigid structural elements in the form of trusses is shown in window  722  The use of trusses, particularly octet-like trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  720  and  722   
   It is appreciated that type D saddle elements are each circumscribed by four adjacent non-cubic rectangular parallelepipeds having a common edge, whose side dimensions X, Y &amp; Z are not all equal  FIG. 15  illustrates a type D saddle element which is circumscribed by four adjacent rectangular parallelepipeds having a common edge, designated by reference numeral  724 , whose side dimensions X, Y &amp; Z are not all equal 
   Type D saddle elements are characterized in that they have eight edges, designated in  FIG. 15  by reference numerals  725 ,  726 ,  727 ,  728 ,  729 ,  730 ,  731  and  732 , each defined by a diagonal extending along a side surface of a rectangular parallelepiped The side surfaces whose diagonals define edges  725 ,  726 ,  727 ,  728 ,  729 ,  730 ,  731  and  732  are respectively designated by reference numerals  735 ,  736 ,  737 ,  738 ,  739 ,  740 ,  741  and  742  Surfaces  735  and  736  lie in the same plane, which extends parallel to and spaced from the plane of surfaces  739  and  740  Surfaces  737  and  738  lie in a common plane, which is perpendicular to planes  735 ,  736 ,  739  and  740 . Surfaces  737  and  738  lie in parallel spaced relationship with surfaces  741  and  742 , which both lie in a common plane Eight junctions, designated by reference numerals  743 ,  744 ,  745 ,  746 ,  747 ,  748 ,  749  and  750  are defined by the eight edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  720 . According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet-like trusses, linear combinations of octahedron-like structures and tetrahedron-like structures, as shown in window  722 . Rigid structural elements of this type are known, for example in U.S. Pat. No. 4,869,041, for other applications 
   Reference is now made to  FIG. 16 , which is a simplified illustration of a junction of rigid structural elements in the embodiment of FIG.  15 .  FIG. 16  shows the junction  760  of three rigid structural elements, designated by reference numerals  762 ,  764  and  766  It is seen that the junction of rigid structural elements  762 ,  764  and  766  defines octahedron-like pair of pyramids having a common base. This pair of pyramids, designated by reference numeral  770 , is common to all three elements 
   Reference is now made to  FIG. 17 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including two type E saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of cubes The rigid structural elements define part of an octet structure. 
   As seen in  FIG. 17 , the building structure comprises type E saddle elements  810  and  814  in two different orientations. A single type E saddle element surrounded by rigid structural elements in the form of beams is shown in window  820  and a single type E saddle element surrounded by rigid structural elements in the form of trusses is shown in window  822 . The use of trusses, particularly octet trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  820  and  822   
   The type E saddle elements in this embodiment are characterized in that they define three 60 degree junctions and two 90 degree junctions It is appreciated that type E saddle elements are each circumscribed by three adjacent cubes having a common edge, whose side dimensions X, Y &amp; Z are all equal.  FIG. 17  illustrates a type E saddle element which is circumscribed by three adjacent rectangular parallelepipeds having a common edge, designated by reference numeral  824 , whose side dimensions X, Y &amp; Z are all equal, thus defining three adjacent cubes 
   Type E saddle elements are characterized in that they have four edges, designated in  FIG. 17  by reference numerals  825 ,  826 ,  827  and  828 , each defined by a diagonal extending along a side surface of a rectangular parallelepiped, and an edge  829 , which extends along side surfaces of two rectangular parallelepipeds and is double the length of each of the remaining four edges. The side surfaces whose diagonals define edges  825 ,  826 ,  827  and  828  are respectively designated by reference numerals  835 ,  836 ,  837  and  838  The side surfaces whose diagonals define edge  829  are designated by reference numerals  839  and  840   
   Surfaces  835  and  836  lie in the same plane, which extend perpendicular to the plane of surfaces  837  and  838  These two planes lie perpendicular to a plane of surfaces  839  and  840  Five junctions, designated by reference numerals  843 ,  844 ,  845 ,  846  and  847  are defined by the five edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  820  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet trusses, linear combinations of octahedrons and tetrahedrons, as shown in window  822 . Rigid structural elements of this type are known, for example in U.S. Pat. No. 4,869,041, for other applications 
   Reference is now made to  FIG. 18 , which is a simplified illustration of a junction of rigid structural elements in the embodiment of  FIG. 17   FIG. 18  shows the junction  860  of three rigid structural elements, designated by reference numerals  862 ,  864  and  866  It is seen that the junction of rigid structural elements  862 ,  864  and  866  defines an octahedron  870 , which is common to all three elements. 
   Reference is now made to  FIG. 19 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including two type E saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of non-cubic rectangular parallelepipeds. The rigid structural elements define part of an octet-like structure 
   As seen in  FIG. 19 , the building structure comprises type E saddle elements  910  and  914  in two different orientations A single type E saddle element surrounded by rigid structural elements in the form of beams is shown in window  920  and a single type E saddle element surrounded by rigid structural elements in the form of trusses is shown in window  922 . The use of trusses, particularly octet-like trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  920  and  922 . 
   It is appreciated that type E saddle elements are each circumscribed by three adjacent non-cubic rectangular parallelepipeds having a common edge, whose side dimensions X, Y &amp; Z are not all equal.  FIG. 19  illustrates a type E saddle element which is circumscribed by three adjacent rectangular parallelepipeds having a common edge, designated by reference numeral  924 , whose side dimensions X, Y &amp; Z are not all equal 
   Type E saddle elements are characterized in that they have four edges, designated in  FIG. 19  by reference numerals  925 ,  926 ,  927  and  928 , each defined by a diagonal extending along a side surface of a rectangular parallelepiped, and an edge  929 , which extends along side surfaces of two rectangular parallelepipeds and normally has a length greater than the length of any of the remaining four edges The side surfaces whose diagonals define edges  925 ,  926 ,  927  and  928  are respectively designated by reference numerals  935 ,  936 ,  937  and  938  The side surfaces whose diagonals define edge  929  are designated by reference numerals  939  and  940 . 
   Surfaces  935  and  936  lie in the same plane, which extends perpendicular to the plane of surfaces  937  and  938  These two planes lie perpendicular to a plane of surfaces  939  and  940  Five junctions, designated by reference numerals  943 ,  944 ,  945 ,  946  and  947  are defined by the five edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  920  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet-like trusses, linear combinations of octahedron-like structures and tetrahedron-like structures, as shown in window  922 . Rigid structural elements of this type are known, for example in U.S. Pat. No. 4,869,041, for other applications 
   Reference is now made to  FIG. 20 , which is a simplified illustration of a junction of rigid structural elements in the embodiment of  FIG. 19   FIG. 20  shows the junction  960  of three rigid structural elements, designated by reference numerals  962 ,  964  and  966  It is seen that the junction of rigid structural elements  962 ,  964  and  966  defines octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  970 , is common to all three elements 
   Reference is now made to  FIG. 21 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including three type F saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of cubes The rigid structural elements define part of an octet structure 
   As seen in  FIG. 21 , the building structure comprises type F saddle elements  1010 ,  1012  and  1014  in two different orientations A single type F saddle element surrounded by rigid structural elements in the form of beams arranged to define part of an octet structure is shown in window  1020  and a single type F saddle element surrounded by rigid structural elements in the form of trusses arranged to define part of an octet structure is shown in window  1022  The use of trusses, particularly octet trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  1020  and  1022   
   The type F saddle elements in this embodiment are characterized in that they define two 60 degree junctions and four 120 degree junctions. It is appreciated that type F saddle elements are each circumscribed by four cubes all having a common edge.  FIG. 21  illustrates a type F saddle element which is circumscribed by four rectangular parallelepipeds having a common edge) and whose side dimensions X, Y &amp; Z are all equal, thus defining cubes 
   Type F saddle elements are characterized in that they have six edges, designated in  FIG. 21  by reference numerals  1025 ,  1026 ,  1027 ,  1028 ,  1029  and  1030 , each defined by a diagonal extending along a side surface of the rectangular parallelepiped The side surfaces whose diagonals define edges  1025 ,  1026 ,  1027 ,  1028 ,  1029  and  1030  are respectively designated by reference numerals  1035 ,  1036 ,  1037 ,  1038 ,  1039  and  1040  Surfaces  1037  and  1040  lie in the same plane, which extends perpendicular to the remaining surfaces  1035 ,  1036 ,  1038  and  1039  Surfaces  1035 ,  1030  and  1040  are all mutually perpendicular Surfaces  1035  and  1038  are in mutually parallel spaced relationship 
   Six junctions, designated by reference numerals  1045 ,  1046 ,  1047 ,  1048 ,  1049  and  1050 , are defined by the six edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  1020  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet trusses, linear combinations of octahedrons and tetrahedrons, as shown in window  1022  Rigid structural elements of this type are known, for example in U.S. Pat. No. 4,869,041, for other applications 
   Reference is now made to  FIGS. 22A &amp; 22B , which are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 21   FIG. 22A  shows the junction  1060  of three rigid structural elements, designated here and in  FIG. 21  by reference numerals  1062 ,  1064  and  1066  It is seen that the junction of rigid structural elements  1062 ,  1064  and  1066  defines an octahedron  1070 , which is common to all three elements 
     FIG. 22B  shows the junction  1080  of two rigid structural elements, designated here and in  FIG. 21  by reference numerals  1082  and  1084 . It is seen that the junction of rigid structural elements  1082  and  1084  is also an octahedron  1088 , which is common to both elements 
   Reference is now made to  FIG. 23 , which is a simplified illustration of a building, structure, constructed and operative in accordance with another preferred embodiment of the present invention including three type F saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of non-cubic rectangular parallelepipeds The rigid structural elements define part of an octet-like structure 
   As seen in  FIG. 23  the building structure comprises type F saddle elements  1110 ,  1112  and  1114  in two different orientations A single type F saddle element surrounded by rigid structural elements in the form of beams is shown in window  1120  and a single type F saddle element surrounded by rigid structural elements in the form of trusses is shown in window  1122  The use of trusses, particularly octet-like trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  1120  and  1122   
   The type F saddle elements in this embodiment are characterized in that they define six junctions which are not necessarily identical It is appreciated that type F saddle elements are each circumscribed by a single rectangular parallelepiped, whose side dimensions X, Y &amp; Z may be, but need not be, equal.  FIG. 23  illustrates a type F saddle element which is circumscribed by three rectangular parallelepipeds, whose side dimensions X,Y &amp; Z are not all equal 
   Type F saddle elements are characterized in that they have six edges, designated in  FIG. 21  by reference numerals  1125 ,  1126 ,  1127 ,  1128 ,  1129  and  1130 , each defined by a diagonal extending along a side surface of the rectangular parallelepiped The side surfaces whose diagonals define edges  1125 ,  1126 ,  1127 ,  1128 ,  1129  and  1130  are respectively designated by reference numerals  1135 ,  1136 ,  1137 ,  1138 ,  1139  and  1140  Surfaces  1137  and  1140  lie in the same plane, which extends perpendicular to the remaining surfaces  1135 ,  1136 ,  1138  and  1139  Surfaces  1135 ,  1136  and  1140  are all mutually perpendicular Surfaces  1135  and  1138  are in mutually parallel spaced relationship 
   Six junctions, designated by reference numerals  1145 ,  1146 ,  1147 ,  1148 ,  1149  and  1150 , are defined by the six edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  1120 . According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses most preferably as octet-like trusses, linear combinations of octahedron-like structures and tetrahedron-like structures, as shown in window  1122   
   Reference is now made to  FIGS. 24A &amp; 24B , which are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 23   FIG. 24A  shows the junction  1160  of three rigid structural elements, designated here and in  FIG. 23  by reference numerals  1162 ,  1164  and  1166  It is seen that the junction of rigid structural elements  1162 ,  1164  and  1166  defines an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  1170 , is common to all three elements 
     FIG. 24B  shows a junction  1180  of two rigid structural elements designated here and in  FIG. 23  by reference numerals  1182  and  1184  It is seen that the junction of rigid structural elements  1182  and  1184  is also an octahedron-like pair of pyramids leaving a common base This pair of pyramids, designated by reference numeral  1190 , is common to both elements 
   Reference is now made to  FIG. 25 , which is a simplified illustration of a building structure, constructed and operative in accordance with a preferred embodiment of the present invention including three type G saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of cubes The rigid structural elements define part of an octet structure. 
   As seen in  FIG. 25 , the building structure comprises type G saddle elements  1210 ,  1212  and  1214  in two different orientations A single type G saddle elements surrounded by rigid structural elements in the form of beams arranged to define part of an octet structure is shown in window  1220  and a single type G saddle element surrounded by rigid structural elements in the form of trusses arranged to define part of an octet structure is shown in window  1222  The use of trusses, particularly octet trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  1920  and  1222   
   The type G saddle elements in this embodiment are characterized in that they define three 60 degree junctions and one 90 degree junction and one 120 degree junction It is appreciated that type C saddle elements are each circumscribed by two cubes all having, a common side surface  FIG. 25  illustrates a type G saddle element which is circumscribed by two rectangular parallelepipeds having a common edge and whose side dimensions X, Y &amp; Z are all equal, thus defining cubes 
   Type G saddle elements are characterized in that they have five edges, designated in  FIG. 25 , by reference numerals  1225 ,  1226 ,  1227 ,  1228  and  1229  each defined by a diagonal extending along a side surface of the rectangular parallelepiped The side surfaces whose diagonals define edges  1225 ,  1226 ,  1227 ,  1228  and  1229  are respectively designated by reference numerals  1235 ,  1236 ,  1237 ,  1238  and  1239 . Surfaces  1237  and  1238  lie in the same plane, which extends parallel to and in spaced relationship to surface  1235  Surfaces  1235 ,  1237  and  1238  are perpendicular to the remaining surfaces  1236  and  1239 , which are mutually perpendicular. 
   Five junctions, designated by reference numerals  1245 ,  1246 ,  1247 ,  1248  and  1249 , are defined by the five edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  1220  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet trusses, linear combinations of octahedrons and tetrahedrons, as shown in window  1222 . Rigid structural elements of this type are known for example in U.S. Pat. No. 4,869,041, for other applications 
   Reference is now made to  FIGS. 26A &amp; 26B , which are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 25   FIG. 26A  shows the junction  1260  of four rigid structural elements, designated here and in  FIG. 25  by reference numerals  1262 ,  1264 ,  1266  and  1268  It is seen that the junction of rigid structural elements  1262 ,  1264 ,  1266  and  1268  defines an octahedron  1270 , which is common to all four elements 
     FIG. 26B  shows the junction  1280  of three rigid structural elements, designated here and in  FIG. 25  by reference numerals  1282 ,  1284  and  1286  It is seen that the junction of rigid structural elements  1282 ,  1284  and  1286  is also an octahedron  1288 , which is common to all three elements. 
   Reference is now made to  FIG. 27 , which is a simplified illustration of a building structure, constructed and operative in accordance with another preferred embodiment of the present invention including three type G saddle elements as well as rigid structural elements fixed to the edges thereof and lying along diagonals of sides of non-cubic rectangular parallelepipeds The rigid structural elements define part of an octet-like structure 
   As seen in  FIG. 27 , the building structure comprises type G saddle elements  1310 ,  1312  and  1314  in three different orientations A single type G saddle element surrounded by rigid structural elements in the form of beams is shown in window  1320  and a single type G saddle element surrounded by rigid structural elements in the form of trusses is shown in window  1322  The use of trusses, particularly octet-like trusses, enables significantly increased dimensions to be spanned, as illustrated symbolically by the size difference between the saddle elements shown in windows  1320  and  1322 . 
   The type G saddle elements in this embodiment are characterized in that they define five junctions which are not necessarily identical. It is appreciated that type G saddle elements are each circumscribed by a single rectangular parallelepiped, whose side dimensions X, Y &amp; Z may be, but need not be, equal.  FIG. 27  illustrates a type G saddle element which is circumscribed by two rectangular parallelepipeds, whose side dimensions X, Y &amp; Z are not all equal. 
   Type G saddle elements are characterized in that they have five edges, designated in  FIG. 27  by reference numerals  1325 ,  1326 ,  1327 ,  1328  and  1329 , each defined by a diagonal extending along a side surface of the rectangular parallelepiped. The side surfaces whose diagonals define edges  1325 ,  1326 ,  1327 ,  1328  and  1329  are respectively designated by reference numerals  1335 ,  1336 ,  1337 ,  1338  and  1339  Surfaces  1337  and  1338  lie in the same plane, which extends parallel to and in spaced relationship to surface  1335  Surfaces  1335 ,  1337  and  1338  are perpendicular to the remaining surfaces  1336  and  1339 , which are mutually perpendicular 
   Five junctions, designated by reference numerals  1345 ,  1346 ,  1347 ,  1348  and  1349 , are defined by the five edges, each junction being located at the meeting of the ends of two adjacent edges 
   The rigid structural elements may be any suitable rigid structural elements, such as beams, as shown in window  1320  According to a preferred embodiment of the present invention, rigid structural elements are constructed as trusses, most preferably as octet-like trusses, linear combinations of octahedron-like structures and tetrahedron-like structures, as shown in window  1322   
   Reference is now made to  FIGS. 28A &amp; 28B , which are simplified illustrations of two junctions of rigid structural elements in the embodiment of  FIG. 27   FIG. 28A  shows the junction  1360  of four rigid structural elements, designated by reference numerals  1362 ,  1364 ,  1366  and  1368  It is seen that the junction of rigid structural elements  1362 ,  1364 ,  1366  and  1368  defines an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  1370 , is common to all three elements 
     FIG. 28B  shows a junction  1380  of three rigid structural elements designated here and in  FIG. 27  by reference numerals  1382 ,  1384  and  1386 . It is seen that the junction of rigid structural elements  1382 ,  1384  and  1386  is also an octahedron-like pair of pyramids having a common base This pair of pyramids, designated by reference numeral  1390 , is common to both elements. 
   Reference is now made to  FIGS. 29A ,  29 B,  29 C and  29 D, which are simplified illustrations of four variations of rigid structural elements useful in various embodiments of the present invention 
     FIG. 29A  illustrates a truss structure comprising a linear arrangement of octahedrons and tetrahedrons defining an octet geometry The truss structure is formed of struts having identical lengths and octet joints. 
     FIG. 29B  illustrates a truss structure comprising a linear arrangement of half-octahedrons and tetrahedrons defining an octet geometry The truss structure is formed of struts having identical lengths and octet joints This structure is more economical in terms of material than that of FIG.  29 A. 
     FIG. 29C  illustrates a truss structure comprising a pre-fabricated linear arrangement  1392  of half-octahedrons and tetrahedrons defining an octet geometry such as that in  FIG. 29B , or alternatively that in  FIG. 29A , which may be coupled on-site with octahedron elements  1394  to define various structures 
     FIG. 29D  illustrates a truss structure comprising a pre-fabricated linear rigid structural element  1396  of any suitable construction, which may be coupled on-site with octahedron elements  1398  to define various structures 
   Reference is now made to  FIGS. 30A ,  30 B,  30 C and  30 D, which are simplified illustrations of four further variations of rigid structural elements useful in various embodiments of the present invention 
     FIG. 30A  illustrates a truss structure comprising a linear arrangement of octahedron-like structures and tetrahedron-like structures defining an octet-like geometry The truss structure is formed of struts having octet-like joints. 
     FIG. 30B  illustrates a truss structure comprising a linear arrangement of half-octahedron-like structures and tetrahedron-like structures defining an octet-like geometry The truss structure is formed of struts octet-like joints In certain cases, this structure is more economical in terms of material than that of FIG.  30 A. 
     FIG. 30C  illustrates a truss structure comprising a pre-fabricated linear arrangement  1395  of half-octahedron-like structures and tetrahedron-like structures defining an octet geometry such as that in  FIG. 30B , or alternatively that in  FIG. 30A , which may be coupled on-site with octahedron-like structure elements  1396  to define various structures 
     FIG. 30D  illustrates a truss structure comprising a pre-fabricated linear rigid structural element  1397  of any suitable construction, which may be coupled on-site with octahedron-like structure elements  1398  to define various structures 
   It is appreciated that truss structures which are combinations of the truss structures described hereinabove may also be employed The various truss structures may also be provided with additional reinforcement along all or part of their length Pretensioned rigid structural elements and any other suitable rigid structural elements may also be employed. 
   Reference is now made to  FIGS. 31A and 31B , which are respective isometric and perspective illustrations of a structure comprising four type A saddle elements  1400 , in two different orientations, arranged in an octet structure and rigid structural elements  1402  incorporating an octet truss structure 
   Reference is now made to  FIGS. 32A and 32B , which are respective isometric and perspective illustrations of a structure comprising four type A saddle elements  1404  in two different orientations arranged in an octet-like structure and rigid structural elements  1406  incorporating an octet-like truss structure. 
   Reference is now made to  FIGS. 33A and 33B , which are respective isometric and perspective illustrations of a structure comprising four type A saddle elements  1410 , in two different orientations, arranged in an octet structure and rigid structural elements  1412  incorporating an octet truss structure 
   Reference is now made to  FIGS. 34A and 34B , which are respective isometric and perspective illustrations of a structure comprising four type A saddle elements  1414  in two different orientations arranged in an octet-like structure and rigid structural elements  1416  incorporating an octet-like truss structure 
   It is noted from a comparison of  FIGS. 31A-32B  and  33 A- 34 B that although the structures both comprise identical elements, very different configurations are realized 
   Reference is now made to  FIGS. 35A and 35B , which are respective isometric and perspective illustrations of a structure comprising four type B saddle elements  1420 , in four different orientations, arranged in an octet structure and rigid structural elements  1422  incorporating an octet truss structure 
   Reference is now made to  FIGS. 36A and 36B , which are respective isometric and perspective illustrations of a structure comprising four type A saddle elements  1424  in two different orientations arranged in an octet-like structure and rigid structural elements  1426  incorporating an octet-like truss structure 
   Reference is now made to  FIGS. 37A and 37B , which are respective isometric and perspective illustrations of a structure comprising two type A saddle elements  1430 , in two different orientations, arranged in an octet structure and rigid structural elements  1432  incorporating an octet truss structure. 
   Reference is now made to  FIGS. 38A and 38B , which are respective isometric and perspective illustrations of a structure comprising two type A saddle elements  1434  in two different orientations arranged in an octet-like structure and rigid structural elements  1436  incorporating an octet-like truss structure 
   Reference is now made to  FIGS. 39A and 39B , which are respective isometric and perspective illustrations of a structure comprising ten type B saddle elements  1440 , in six different orientations, arranged in an octet structure and rigid structural elements  1442  incorporating an octet truss structure 
   Reference is now made to  FIGS. 40A and 40B , which are respective isometric and perspective illustrations of a structure comprising ten type B saddle elements  1444  in six different orientations arranged in an octet-like structure and rigid structural elements  1446  incorporating an octet-like truss structure 
   It is noted, from a consideration of  FIGS. 39A-40B , that a two layered structure is realized 
   Reference is now made to  FIGS. 41A and 41B , which are respective isometric and perspective illustrations of a structure comprising twelve type B saddle elements  1450 , in twelve different orientations, arranged in an octet structure and rigid structural elements  1452  incorporating an octet truss structure 
   Reference is now made to  FIGS. 42A and 42B , which are respective isometric and perspective illustrations of a structure comprising twelve type B saddle elements  1454  in twelve different orientations arranged in an octet-like structure and rigid structural elements  1456  incorporating an octet-like truss structure. 
   It is noted from a consideration of  FIGS. 41A-42B  that an enclosure is realized 
   Reference is now made to  FIGS. 43A and 43B , which are respective isometric and perspective illustrations of a structure comprising eleven type B saddle elements  1460 , in eleven different orientations, arranged in an octet structure and rigid structural elements  1462  incorporating an octet truss structure. 
   Reference is now made to  FIGS. 44A and 44B , which are respective isometric and perspective illustrations of a structure comprising eleven type B saddle elements  1464  in eleven different orientations arranged in an octet-like structure and rigid structural elements  1466  incorporating an octet-like truss structure. 
   Reference is now made to  FIG. 45 , which is a roof plan view illustration of a structure comprising twelve type A saddle elements  1470  in two different orientations and two type B saddle elements  1472  in the same orientation and rigid structural elements  1474  Locations at which the structure touches a base surface are indicated by circles  1476   
   Reference is now made to  FIGS. 46A and 46B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 45  wherein the type A saddle elements, here designated by reference numerals  1480 , and the type B saddle elements, here designated by reference numeral  1482 , are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1484 , incorporate an octet truss structure. 
   Reference is now made to  FIGS. 47A and 47B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 45  wherein the type A saddle elements, here designated by reference numerals  1490 , and the type B saddle elements, here designated by reference numerals  1492 , are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1494 , incorporate an octet-like truss structure 
   Reference is now made to  FIG. 48 , which is a roof plan view illustration of a structure comprising eight type A saddle elements  1500  in two different orientations and four type B saddle elements  1502  in four different orientations and rigid structural elements  1504  Locations at which the structure touches a base surface are indicated by circles  1506   
   Reference is now made to  FIGS. 49A and 49B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 48  wherein the type A saddle elements, here designated by reference numerals  1510 , and the type B saddle elements, here designated by reference numeral  1512 , are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1514 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 50A and 50B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 48  wherein the type A saddle elements, here designated by reference numerals  1520 , and the type B saddle elements, here designated by reference numerals  1522 , are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1524 , incorporate an octet-like truss structure 
   Reference is now made to  FIG. 51 , which is a roof plan view illustration of a structure comprising twelve type A saddle elements  1530  in two different orientations and eight type B saddle elements  1532  in eight different orientations and rigid structural elements  1534  Locations at which the structure touches a base surface are indicated by circles  1536   
   Reference is now made to  FIGS. 52A and 52B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 51  wherein the type A saddle elements, here designated by reference numerals  1540 , and the type B saddle elements, here designated by reference numeral  1542 , are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1544 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 53A and 53B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 51  wherein the type A saddle elements, here designated by reference numerals  1550 , and the type B saddle elements, here designated by reference numerals  1552 , are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1554 , incorporate an octet-like truss structure. 
   Reference is now made to  FIG. 54 , which is a roof plan view illustration of a structure comprising two type A saddle elements  1560  in two different orientations, eleven type B saddle elements  1562  in seven different orientations and three type C saddle elements  1564  and rigid structural elements  1566 . Locations at which the structure touches a base surface are indicated by circles  1568   
   Reference is now made to  FIGS. 55A and 55B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 54  wherein the type A saddle elements, here designated by reference numerals  1570 , the type B saddle elements, here designated by reference numeral  1572 , and the type C saddle elements, here designated by reference numeral  1574 , are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1576 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 56A and 56B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 54  wherein the type A saddle elements, here designated by reference numerals  1580 , the type B saddle elements, here designated by reference numeral  1582  and the type C saddle elements, here designated by reference numerals  1584 , are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1524 , incorporate an octet-like truss structure 
   Reference is now made to  FIG. 57 , which is a roof plan view illustration of a structure comprising, three type B saddle elements  1600  in three different orientations and one type D saddle element  1602  and rigid structural elements  1604 . Locations at which the structure touches a base surface are indicated by circles  1606 . 
   Reference is now made to  FIGS. 58A and 58B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 57  wherein the type B saddle elements, here designated by reference numerals  1610  and the type D saddle element, here designated by reference numeral  1612 , are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1614 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 59A and 59B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 57  wherein the type B saddle elements, here designated by reference numerals  1620  and the type D saddle element, here designated by reference numerals  1622 , are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1624 , incorporate an octet-like truss structure. 
   Reference is now made to  FIG. 60 , which is a roof plan view illustration of a structure comprising four type A saddle elements  1630  in two different orientations, four type B saddle elements  1632  in four different orientations, and three type D saddle elements  1634  in two different orientations and rigid structural elements  1636 . Locations at which the structure touches a base surface are indicated by circles  1638   
   Reference is now made to  FIGS. 61A and 61B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 60  wherein the type A saddle elements, here designated by reference numerals  1640 , the type B saddle elements  1642  and the type D saddle elements, here designated by reference numeral  1644 , are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1646  incorporate an octet truss structure 
   Reference is now made to  FIGS. 62A and 62B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 60  wherein the type A saddle elements, here designated by reference numerals  1650 , the type B saddle elements  1652  and the type D saddle elements, here designated by reference numerals  1654 , are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1656 , incorporate an octet-like truss structure 
   Reference is now made to  FIG. 63 , which is a roof plan view illustration of a structure comprising four type A saddle elements  1660  in two different orientations and twelve type B saddle elements  1662  in four different orientations and rigid structural elements  1664  Locations at which the structure touches a base surface are indicated by circles  1666   
   Reference is now made to  FIGS. 64A and 64B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 63  wherein the type A saddle elements, here designated by reference numerals  1670  and the type B saddle elements  1672 , are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1674 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 65A and 65B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 63  wherein the type A saddle elements, here designated by reference numerals  1680  and the type B saddle elements  1682  are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1684 , incorporate an octet-like truss structure 
   Reference is now made to  FIG. 66 , which is a roof plan view illustration of a structure comprising fourteen type A saddle elements  1700  in two different orientations, four type B saddle elements  1702  in four different orientations, four type D saddle elements  1704  in two different orientations, seven type E saddle elements  1706  all in the same orientation and rigid structural elements  1708  Locations at which the structure touches a base surface are indicated by circles  1709   
   Reference is now made to  FIGS. 67A and 67B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 66  wherein the type A saddle elements, here designated by reference numerals  1710 , the type B saddle elements  1712 , the type D saddle elements  1714 , the type E saddle elements  1716  are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1718 , incorporate an octet truss structure. 
   Reference is now made to  FIGS. 68A and 68B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 66  wherein the type A saddle elements, here designated by reference numerals  1720 , the type B saddle elements  1722 , the type D saddle elements  1724 , the type E saddle elements  1726  are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1728 , incorporate an octet-like truss structure. 
   Reference is now made to  FIG. 69 , which is a roof plan view illustration of a structure comprising twelve type A saddle elements  1730  in two different orientations, 28 type B saddle elements  1732  in eight different orientations, one type D saddle element  1734  and rigid structural elements  1736  Locations at which the structure touches a base surface are indicated by circles  1738   
   Reference is now made to  FIGS. 70A and 70B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 69  wherein the type A saddle elements, here designated by reference numerals  1740 , the type B saddle elements  1742  and the type D saddle element  1744  are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1746 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 71A and 71B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 69  wherein the type A saddle elements, here designated by reference numerals  1750 , the type B saddle elements  1752  and the type D saddle element  1754  are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1756 , incorporate an octet-like truss structure 
   It is appreciated, from a consideration of  FIGS. 69-71B , that a multilayer structure, having a relatively very large free space, is realized. 
   Reference is now made to  FIG. 72 , which is a roof plan view illustration of a structure comprising, four type A saddle elements  1760  in two different orientations, four type B saddle elements  1762  in four different orientations, one type D saddle element  1764  and eight type G saddle elements  1766  in eight different orientations as well as rigid structural elements  1768  Locations at which the structure touches a base surface are indicated by circles  1769   
   Reference is now made to  FIGS. 73A and 73B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 72  wherein the type A saddle elements, here designated by reference numerals  1770 , the type B saddle elements  1772 , the type D saddle element  1774  and the type G saddle elements  1776  are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1778 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 74A and 74B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 72  wherein the type A saddle elements, here designated by reference numerals  1780 , the type B saddle elements  1782 , the type D saddle element  1784  and the type G saddle elements  1786  are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1788 , incorporate an octet-like truss structure. 
   It is appreciated, from a consideration of  FIGS. 72-74B , that a multilayer structure, having a relatively large free space, is realized. 
   Reference is now made to  FIGS. 75A and 75B , which illustrate one example of an integrated structure employing structural elements of the types described hereinabove together with a conventional three-dimensional tensioned cable system for providing enhanced overall constructional efficiency 
   The basic structure of  FIGS. 75A and 75B  is similar to that of  FIGS. 35A and 35B , with the addition of a peripheral tensioned cable  1900  and a center mounted element  1902  which is supported by a pair of crossing cables  1904   
     FIG. 75A  is an isometric illustration of a structure comprising four type B saddle elements  1906 , in four different orientations, arranged in an octet structure and rigid structural elements  1908  incorporating an octet truss structure 
     FIG. 75B  is an isometric illustration of a structure comprising four type B saddle elements  1916 , in four different orientations, arranged in an octet-like structure and rigid structural elements  1918  incorporating an octet-like truss structure. 
   In both  FIGS. 75A &amp; 75B , the crossing cables  1904  support the junction of generally horizontal rigid structural elements  1908  and  1918  and thus enable any of all of the rigid structural elements  1908  and  1918  to be formed with less material and/or fewer struts and joints 
   Reference is now made to  FIGS. 76A &amp; 76B , which illustrate another example of an integrated structure employing structural elements of the types described hereinabove together with a conventional three-dimensional tensioned cable system for providing enhanced overall constructional efficiency. 
   The basic structure of  FIGS. 76A and 76B  is a combination of two structures of, respectively, the types shown in  FIGS. 75A &amp; 75B  together with a tent-like addition preferably embodied in a pyramidal tensioned membrane (not shown) Each of the structures shown in respective  FIGS. 75A &amp; 75B  includes a peripheral tensioned cable  1920  and a center mounted element  1922  which is supported by a pair of crossing cables  1924  A central shaft  1926  is supported well above the ground surface by two pairs of crossings cables  1928  and  1930  Crossing cables  1928  engage a bottom location  1932  of central shaft  1926 , while crossing cables  1930  engage a central location  1934  of central shaft  1926   
     FIG. 76A  is an isometric illustration of a structure comprising six type B saddle elements  1946 , in four different orientations, arranged in an octet structure, and rigid structural elements  1948  incorporating an octet truss structure. 
     FIG. 76B  is an isometric illustration of a structure comprising six type B saddle elements  1956 , in four different orientations, arranged in an octet-like structure, and rigid structural elements  1958  incorporating an octet-like truss structure. 
   Reference is now made to  FIG. 77 , which is a roof plan view illustration of a structure comprising four type A saddle elements  1960  in two different orientations, thirteen type B saddle elements  1962  in seven different orientations as well as rigid structural elements  1966  Locations at which the structure touches a base surface are indicated by circles  1968  It is appreciated that the structure of  FIG. 77  incorporates that of  FIGS. 76A &amp; 76B   
   Reference is now made to  FIGS. 78A and 78B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 77  wherein the type A saddle elements, here designated by reference numerals  1970  and the type B saddle elements  1972  are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  1976 , incorporate an octet truss structure. 
   Reference is now made to  FIGS. 79A and 79B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 77  wherein the type A saddle elements, here designated by reference numerals  1980  and the type B saddle elements  1982  are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  1986 , incorporate an octet-like truss structure 
   It is appreciated from a consideration of  FIGS. 76A ,  76 B and  77 - 79 B that a multilayer structure is provided including a pyramidal tensioned membrane  1990  which is supported by a tensioned cable system as described A relatively large free space is realized 
   Reference is now made to  FIGS. 80A and 80B , which are, respectively, a roof plain view and an isometric illustration of an alternative realization of the structure of  FIGS. 76A-79B , wherein a pyramidal tensioned membrane  1992  is supported by a truss structure  1994 , which may form part of an octet structure or octet-like structure and may incorporate an octet or octet-like truss structure 
   Reference is now made to  FIG. 81 , which is a roof plan view illustration of a structure comprising four type F saddle elements  2000 , in four different orientations, as well as rigid structural elements  2002  and a pyramidal tensioned membrane  2004  Locations at which the structure touches a base surface are indicated by circles  2006   
   Reference is now made to  FIGS. 82A and 82B , which are respective isometric and perspective illustrations of one embodiment of the structure of  FIG. 81  wherein the type F saddle elements, here designated by reference numerals  2010 , are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  2012 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 83A and 83B , which are respective isometric and perspective illustrations of another embodiment of the structure of  FIG. 81  wherein the type F saddle elements, here designated by reference numerals  2020 , are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  2022 , incorporate an octet-like truss structure 
   It is appreciated from a consideration of FIGS.  81  and  82 A- 83 B that a multilayer structure is provided wherein a second layer is provided by pyramidal tensioned membrane  2004  which is supported by a tensioned cable system as described hereinabove. A relatively large free space is realized. 
   Reference is now made to  FIG. 84 , which is a simplified illustration of a structure employing a single type D saddle element. Such an element is shown at reference numeral  622  in the structure of  FIG. 13 , albeit in a different orientation 
   Reference is now made to  FIG. 85 , which illustrates a structure similar to that shown in  FIG. 84  with the addition of a pair of crossed rigid structural elements  2100  The addition of cross rigid structural elements redefines the type D saddle element shown in  FIG. 84  as a plurality of saddle elements of a different type. 
   Reference is now made to  FIG. 86 , which is a roof plan view illustration of a structure comprising  22  type A saddle elements  2200  in two different orientations,  71  type B saddle elements  2202  in twelve different orientations, three type C saddle elements  2204  in two different orientations, one type D saddle element  2206 , two type E saddle elements  2208  in two different orientations, four type F saddle elements  2210  in a single orientation and two type G saddle elements  2212  in two different orientations as well as rigid structural elements  2214  Locations at which the structure touches a base surface are indicated by circles  2216   
   The structure of  FIG. 86  also includes first and second pyramidal tensioned membranes  2218 , a structure of the type illustrated in  FIG. 85 , here designated by reference numeral  2220 , and an arch  2222  The structure of  FIG. 86  also preferably includes curtain walls  2224 , typically formed of glass, which are at least partially supported by the rigid structural elements  2214  The structure of  FIG. 86  is also characterized in that mechanical systems, such as air conditioning systems  2226 , can be supported at least partially by the rigid structural elements  2214   
   Reference is now made to  FIGS. 87A ,  87 B and  87 C, which are three elevation view illustrations of one embodiment of the structure of  FIG. 86  Reference is also made to  FIG. 88 , which is an isometric illustration of the embodiment of  FIGS. 87A-87C , and to  FIGS. 89A ,  89 B and  89 C, which are three perspective illustrations of the embodiment of  FIGS. 87A-88  In  FIGS. 87A-89C , the type A saddle elements  2230 , the type B saddle elements  2232 , the type C saddle elements  2234 , the type D saddle element  2236 , the type E saddle elements  2238 , the type F saddle elements  2240  and the type G saddle elements  2242  are arranged in an octet structure and the rigid structural elements, here designated by reference numerals  2244 , incorporate an octet truss structure 
   Reference is now made to  FIGS. 90A ,  90 B and  90 C, which are three elevation view illustrations of another embodiment of the structure of  FIG. 86  Reference is also made to  FIG. 91 , which is an isometric illustration of the embodiment of  FIGS. 90A-90C , and to  FIGS. 92A ,  92 B and  92 C, which are three perspective illustrations of the embodiment of  FIGS. 90A-91 . In  FIGS. 90A-92C , the type A saddle elements  2250 , the type B saddle elements  2252 , the type C saddle elements  2254 , the type D saddle element  2256 , the type E saddle elements  2258 , the type F saddle elements  2260 , and the type G saddle elements  2262  are arranged in an octet-like structure and the rigid structural elements, here designated by reference numerals  2264 , incorporate an octets like truss structure 
   It is appreciated that even though the rigid structural elements shown in the illustrated embodiments appear to be uncovered, they may be uncovered or covered by any suitable material 
   It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specification and which are not in the prior art.