Abstract:
A sectional cubic block includes a plurality of layers of structural elements, a smallest one of which is an elementary cube and the other ones are proportionally increased in dimensions based on the elementary cube and all include three plane walls that separately extend in directions of x, y and z axes and therefore define an inner space adapted to receive a next smaller structural elements therein. Each of the structural elements, except the smallest one, is formed from a plurality of elementary frames sequentially proportionally increased in dimensions based on the elementary cube. Each of the elementary frames includes three continued right-angled parts that are respectively included in three planes extended in the directions of x, y and z axes. This particular configuration of the elementary frames enables children to freely stack the elementary frames to create many changeful shapes.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a sectional cubic block that includes a plurality of structural elements, each of which forms a layer of the sectional cubic block and includes a plurality of elementary frames. Through staking these elementary frames, children could extend their imagination to create numerous changeful and balanced shapes.  
           [0002]    Children need suitable “exercises” in the process of development of their brain and muscles, so that they could think and develop the ability of balance. Blocks are most frequently recommended by experts as a constructive toy for children because children observe and manipulate blocks to organize scattered pieces into a complete shape through repeated consideration and assembling. In the process of assembling blocks into a complete shape, children naturally develop and understand the concept of space, the relation between individual parts and a whole body, and the concept of quantity. With blocks, children could embody and enjoy their imaginations. From the building of stable three-dimensional shapes, children are well trained in their mental ability. Thus, blocks are actually a toy having substantial meaning to children.  
           [0003]    However, a really good set of blocks capable of achieving the above brain-training purpose is absolutely not a group of some blocks having different geometrical shapes. An ideal set of blocks includes preferably elementary items that have repeated and ingenious configurations to enable easy holding and assembling thereof, so that numerous interesting, changeful, and balanced structures could be created. It is a pity that we do not easily find such blocks in the markets.  
         SUMMARY OF THE INVENTION  
         [0004]    It is therefore a primary object of the present invention to provide a sectional cubic block that includes a plurality of elementary members having different sizes but a similar configuration, so that the sectional cubic block could be disassembled into separate parts and reassembled with these parts into unlimited numbers of three-dimensional shapes, while all the created shapes have multi-layered, contoured, and balanced structures.  
           [0005]    To achieve the above and other objects, the sectional cubic block of the present invention mainly includes a plurality of layers of structural elements, a smallest one of which is an elementary cube and the other ones are proportionally increased in dimensions based on the elementary cube and all include three plane walls that separately extend in directions of x, y and z axes and therefore define an inner space adapted to receive a next smaller structural elements therein. Each of the structural elements, except the smallest one, is formed from a plurality of elementary frames sequentially proportionally increased in dimensions based on the elementary cube. Each of the elementary frames that are not the elementary cubes is included in a virtual cubic solid and constitutes two adjacent edges of each side of the virtual cubic solid. That is, each of the elementary frames that are not the elementary cubes includes three continued right-angled parts that are respectively included in three planes extended in the directions of x, y and z axes. This particular configuration of the elementary frames enables children to freely stack the elementary frames to create many changeful shapes. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein  
         [0007]    [0007]FIG. 1 is an assembled perspective view showing an exemplified five-layer sectional cubic block according to a first embodiment of the present invention;  
         [0008]    [0008]FIG. 2 is an exploded perspective view of the five-layer sectional cubic block of FIG. 1 showing five structural elements thereof;  
         [0009]    [0009]FIG. 3 is the first and the largest one of the five structural elements of FIG. 2 viewing from an outer side thereof;  
         [0010]    [0010]FIG. 4 is an exploded perspective view of the structural element of FIG. 3 showing five elementary frames thereof;  
         [0011]    [0011]FIG. 5 is the second one of the five structural elements of FIG. 2 viewing from an outer side thereof;  
         [0012]    [0012]FIG. 6 is an exploded perspective view of the structural element of FIG. 5 showing four elementary frames thereof;  
         [0013]    [0013]FIG. 7 is the third one of the five structural elements of FIG. 2 viewing from an outer side thereof;  
         [0014]    [0014]FIG. 8 is an exploded perspective view of the structural element of FIG. 7 showing three elementary frames thereof;  
         [0015]    [0015]FIG. 9 is the fourth one of the five structural elements of FIG. 2 viewing from an outer side thereof;  
         [0016]    [0016]FIG. 10 is an exploded perspective view of the structural element of FIG. 9 showing two elementary frames thereof;  
         [0017]    [0017]FIG. 11 is an exploded perspective view of the outmost and the largest one of the five elementary frames of the structural element of FIG. 3;  
         [0018]    [0018]FIG. 12 is an exploded perspective view of the second one of the five elementary frames of the structural element of FIG. 3;  
         [0019]    [0019]FIG. 13 is an exploded perspective view of the third one of the five elementary frames of the structural element of FIG. 3;  
         [0020]    [0020]FIG. 14 is an exploded perspective view of the fourth one of the five elementary frames of the structural element of FIG. 3;  
         [0021]    [0021]FIG. 15 is an exploded perspective view showing the sequence of assembling different elementary frames of FIGS. 4, 6,  8  and  10  to form a first special shape;  
         [0022]    [0022]FIG. 16 is an assembled perspective view of the first shape formed from the elementary frames of FIG. 15;  
         [0023]    [0023]FIG. 17 is an exploded perspective view showing the sequence of assembling different elementary frames of FIGS. 4, 6,  8  and  10  to form a second special shape;  
         [0024]    [0024]FIG. 18 is an assembled perspective view of the second shape formed from the elementary frames of FIG. 17;  
         [0025]    [0025]FIG. 19 is an exploded perspective view showing the sequence of assembling different elementary frames of FIGS. 4, 6,  8  and  10  to form a third special shape;  
         [0026]    [0026]FIG. 20 is an assembled perspective view of the third shape formed from the elementary frames of FIG. 19;  
         [0027]    [0027]FIG. 21 is an assembled perspective view showing an exemplified five-layer sectional cubic block according to a second embodiment of the present invention;  
         [0028]    [0028]FIG. 22 is an exploded perspective view of the five-layer sectional cubic block of FIG. 21 showing five structural elements thereof;  
         [0029]    [0029]FIG. 23 is the first and the largest one of the five structural elements of FIG. 22 viewing from an outer side thereof;  
         [0030]    [0030]FIG. 24 is an exploded perspective view of the structural element of FIG. 23 showing five elementary frames thereof;  
         [0031]    [0031]FIG. 25 is the second one of the five structural elements of FIG. 22 viewing from an outer side thereof;  
         [0032]    [0032]FIG. 26 is an exploded perspective view of the structural element of FIG. 25 showing four elementary frames thereof;  
         [0033]    [0033]FIG. 27 is the third one of the five structural elements of FIG. 22 viewing from an outer side thereof;  
         [0034]    [0034]FIG. 28 is an exploded perspective view of the structural element of FIG. 27 showing three elementary frames thereof;  
         [0035]    [0035]FIG. 29 is the fourth one of the five structural elements of FIG. 22 viewing from an outer side thereof;  
         [0036]    [0036]FIG. 30 is an exploded perspective view of the structural element of FIG. 29 showing two elementary frames thereof;  
         [0037]    [0037]FIG. 31 is an assembled perspective view showing an exemplified five-layer sectional cubic block according to a third embodiment of the present invention;  
         [0038]    [0038]FIG. 32 is an exploded perspective view of the five-layer sectional cubic block of FIG. 31 showing five structural elements thereof;  
         [0039]    [0039]FIG. 33 is the first and the largest one of the five structural elements of FIG. 32 viewing from an outer side thereof;  
         [0040]    [0040]FIG. 34 is an exploded perspective view of the structural element of FIG. 33 showing five elementary frames thereof;  
         [0041]    [0041]FIG. 35 is the second one of the five structural elements of FIG. 32 viewing from an outer side thereof;  
         [0042]    [0042]FIG. 36 is an exploded perspective view of the structural element of FIG. 35 showing four elementary frames thereof;  
         [0043]    [0043]FIG. 37 is the third one of the five structural elements of FIG. 32 viewing from an outer side thereof;  
         [0044]    [0044]FIG. 38 is an exploded perspective view of the structural element of FIG. 37 showing three elementary frames thereof;  
         [0045]    [0045]FIG. 39 is the fourth one of the five structural elements of FIG. 32 viewing from an outer side thereof; and  
         [0046]    [0046]FIG. 40 is an exploded perspective view of the structural element of FIG. 39 showing two elementary frames thereof.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0047]    Please refer to FIG. 1 that shows a sectional cubic block according to a first embodiment of the present invention. The sectional cubic block is formed from a plurality of structural elements. Each structural element forms a layer of the sectional cubic block. The number of the structural elements may be freely increased or decreased. In the illustrated sectional cubic block of FIG. 1, only five structural elements are included for the convenience of explanation of the present invention.  
         [0048]    The sectional cubic block of FIG. 1 is assembled from five layers or five structural elements A, B, C, D and E that are proportionally reduced in dimensions. FIG. 2 is an exploded perspective view showing these five structural elements. As can be seen from FIG. 2, the structural element A is the largest and the first one of these five structural elements, and the structural element E is the smallest and the fifth one and forms an elementary cube in the sectional cubic block of the present invention. The first, the second, the third, and the fourth structural elements A, B, C and D all include three plane walls (A 01 , A 02 , A 03 ), (B 01 , B 02 , B 03 ), (C 01 , C 02 , C 03 ), and (D 01 , D 02 , D 03 ) that extend in three different directions of x, y and z axes and therefore define an inner space A 04 , B 04 , C 04  and D 04 , respectively, for the structural elements A, B, C and D. The structural elements B, C, D and E could be sequentially received in the inner spaces A 04 , B 04 , C 04  and D 04  and thereby form a complete sectional cubic block of the present invention as shown in FIG. 1.  
         [0049]    [0049]FIGS. 3, 5,  7  and  9  sequentially show the structural elements A, B, C and D, viewed from an outer side of these elements. All these structural elements A, B, C and D could be further disassembled into several elementary frames. FIG. 4 shows the first structural element A is disassembled into five elementary frames, which are denoted as A 10 , A 20 , A 30 , A 40  and A 50  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame A 50  is also the smallest structural element E and the elementary cube in the sectional cubic block of the present invention.  
         [0050]    Please refer to FIGS. 2, 5 and  6 . The second structural element B can be similarly disassembled into four elementary frames, which are denoted as B 10 , B 20 , B 30  and B 40  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame B 40  is also the smallest structural element E and the elementary cube in the sectional cubic block of the present invention.  
         [0051]    Please refer to FIGS. 2, 7 and  8 . The third structural element C can be similarly disassembled into three elementary frames, which are denoted as C 10 , C 20  and C 30  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame C 30  is also the smallest structural element E and the elementary cube in the sectional cubic block of the present invention.  
         [0052]    Please refer to FIGS. 2, 9 and  10 . The fourth structural element D can be similarly disassembled into two elementary frames, which are denoted as D 10  and D 20  from the outer or larger one to the inner or smaller one. Wherein, the smaller elementary frame D 20  is also the smallest structural element E and the elementary cube in the sectional cubic block of the present invention.  
         [0053]    As can be seen from FIGS. 4, 6,  8  and  10 , any one of the elementary frames A 10 , A 20 , A 30 , A 40 , B 10 , B 20 , B 30 , C 10 , C 20  and D 10  that are not the elementary cubes may be included in a virtual cubic solid and constitutes two adjacent edges of each side of the virtual cubic solid. That is, each of the elementary frames A 10 , A 20 , A 30 , A 40 , B 10 , B 20 , B 30 , C 10 , C 20  and D 10  includes three connected right-angled parts that are respectively included in three planes extended in the directions of x, y and z axes. The elementary frames A 10 , A 20 , A 30 , A 40 , B 10 , B 20 , B 30 , C 10 , C 20  and D 10  also sequentially define inner spaces A 11 , A 21 , A 32 , A 41 , B 11 , B 21 , B 31 , C 11 , C 21  and D 11 . Please note elementary frames A 10 , A 20 , A 30 , B 10 , B 20  and C 10  also define an opening each, via which inner spaces A 11 , A 21 , A 31 , B 11 , B 21  and C 11  communicate an inner side with an outer side of the elementary frames A 10 , A 20 , A 30 , B 10 , B 20  and C 10 , respectively.  
         [0054]    Please refer to FIGS. 4, 11,  12 ,  13  and  14 . Elementary frames A 10 , A 20 , A 30  and A 40  all are assembled from a plurality of the smallest elementary frames A 50 , each of which is identical to the smallest structural element E of the sectional cubic block of the present invention. As mentioned above, the smallest elementary frames B 40 , C 30  and D 20  all are identical to the smallest structural element E. The smallest structural element E is provided on its six sides with at least one insert bar E 10  and more than one insert hole E 20 . When multiple pieces of smallest structural elements E are connected to one another by inserting the insert bar E 10  of a rear structural element E into an insert hole E 20  of a front structural element E in the manner shown in FIGS.  11  to  14 , elementary frames A 10 ; A 20  and B 10 ; A 30 , B 20  and C 10 ; and A 40 , B 30 , C 20  and D 10  are formed, respectively.  
         [0055]    The elementary frames and/or the structural elements of the sectional cubic block of the present invention may be freely stacked and/or assembled in many different manners and sequences to create unlimited types of shapes that are always in a balanced position. FIGS. 15 through 20 exemplify some of these unique, interesting and balanced shapes.  
         [0056]    Please refer to FIG. 15. The elementary frames A 20 , A 30 , A 40  and A 50  of the first structural element A are sequentially positioned in the inner spaces A 11 , A 21 , A 31  and A 41  defined in the elementary frames A 10 , A 20 , A 30  and A 40 , but not engaged into the openings defined by these elementary frames, such that elementary frames A 10 , A 20 , A 30 , A 40  and A 50  are stacked one by one from bottom to top and from the largest one to the smallest one to form a first unit. Similarly, the elementary frames B 20 , B 30  and B 40  of the second structural element B are sequentially positioned in the inner spaces B 11 , B 21  and B 31  defined in the elementary frames B 10 , B 20  and B 30 , but not engaged into the openings defined by these elementary frames, such that elementary frames B 10 , B 20 , B 30  and B 40  are stacked one by one from bottom to top and from the largest one to the smallest one to form a second unit. Similarly, the elementary frames C 20  and C 30  of the third structural element C are sequentially positioned in the inner spaces C 11  and C 21  defined in the elementary frames C 10  and C 20 , but not engaged into the openings defined by these elementary frames, such that elementary frames C 10 , C 20  and C 30  are stacked one by one from bottom to top and from the largest one to the smallest one to form a third unit. Then, the second unit is stacked on the first unit, the third unit on the second unit, the elementary frame D 10  on the third unit, and the elementary frame D 20  (that is also the structural element E) in the space D 11  defined by the elementary frame D 20 , so that a first special shape as shown in FIG. 16 is obtained. In this shape, each upper unit is projected from a front central position of a lower unit, giving the shape a multi-layer and stepped appearance and well imparting the concept of space.  
         [0057]    [0057]FIGS. 17 and 18 illustrate a second special shape assembled from the structural elements A, B, C, D and E. As shown in FIG. 17, the elementary frames B 20 , B 30  and B 40  of the second structural element B are sequentially positioned in the inner spaces B 11 , B 21  and B 31  defined in the elementary frames B 10 , B 20  and B 30 , but not engaged into the openings defined by these elementary frames, such that elementary frames B 10 , B 20 , B 30  and B 40  are stacked one by one from bottom to top and from the largest one to the smallest one to form a first unit. Similarly, the elementary frames C 20  and C 30  of the third structural element C are sequentially positioned in the inner spaces C 11  and C 21  defined in the elementary frames C 10  and C 20 , but not engaged into the openings defined by these elementary frames, such that elementary frames C 10 , C 20  and C 30  are stacked one by one from bottom to top and from the largest one to the smallest one to form a second unit. Then, the second unit is stacked on the first unit, and the elementary frames D 10  and D 20  are sequentially stacked on a top of the second unit to form a pyramidal shape. Thereafter, the elementary frames A 20 , A 30 , A 40  and A 50  of the first structural element A are sequentially positioned in the inner spaces A 11 , A 21 , A 31  and A 41  defined in the elementary frames A 10 , A 20 , A 30  and A 40 , but not engaged into the openings defined by these elementary frames, such that elementary frames A 10 , A 20 , A 30 , A 40  and A 50  are stacked one by one from bottom to top and from the largest one to the smallest one to form a third unit. The third unit is then moved to a position immediately above the elementary frame D 20  of the pyramidal shape. At this point, the largest elementary frame A 10  falls to locate in front of the elementary frame B 10 , the elementary frame A 20  falls to locate above the elementary frame B 20 , and the elementary frames A 30 , A 40  and A 50  sequentially locate above the elementary frames D 10  and D 20  to finally form a second special shape showing alternately arranged projections and recesses, as shown in FIG. 18.  
         [0058]    [0058]FIGS. 19 and 20 illustrate a third special shape assembled from some of the elementary frames of the present invention. Please refer to FIG. 19. Elementary frames A 10 , A 20  and A 30  are vertically and serially connected to one another using the elementary frames A 40 , B 30  and C 20  as connectors between them, such that elementary frames A 10 , A 20  and A 30  are separately seated and supported in the inner spaces A 41 , B 31  and C 21  of the elementary frames A 40 , B 30  and C 20 . Then, the elementary frame D 10  and the smallest structural element E are sequentially stacked on the elementary frame A 30  to obtain the third special shape as shown in FIG. 20.  
         [0059]    [0059]FIG. 21 shows a sectional cubic block according to a second embodiment of the present invention. This sectional cubic block is also formed from a plurality of structural elements. Each structural element forms a layer of the sectional cubic block. The number of the structural elements may be freely increased or decreased. In the illustrated sectional cubic block of FIG. 21, only five structural elements are included for the convenience of explanation of the present invention.  
         [0060]    The sectional cubic block of FIG. 21 is assembled from five layers or five structural elements F, G, H, I and J that are proportionally reduced in dimensions. FIG. 22 is an exploded perspective view showing these five structural elements. As can be seen from FIG. 22, the structural element F is the largest and the first one of these five structural elements, and the structural element J is the smallest and the fifth one and forms an elementary cube in the sectional cubic block of the present invention. The first, the second, the third, and the fourth structural elements F, G, H and I all include three plane walls (F 01 , F 02 , F 03 ), (G 01 , G 02 , G 03 ), (H 01 , H 02 , H 03 ), and (I 01 , I 02 , I 03 ) that extend in three different directions of x, y and z axes and therefore define an inner space F 04 , G 04 , H 04  and I 04 , respectively, for the structural elements F, G, H and I. The structural elements G, H, I and J could be sequentially received in the inner spaces F 04 , G 04 , H 04  and I 04  and thereby form a complete sectional cubic block of the present invention as shown in FIG. 21.  
         [0061]    [0061]FIGS. 23, 25,  27  and  29  sequentially show the structural elements F, G, H and I, viewed from an outer side of these elements. All these structural elements F, G, H and I could be further disassembled into several elementary frames. FIG. 24 shows the first structural element F is disassembled into five elementary frames, which are denoted as F 10 , F 20 , F 30 , F 40  and F 50  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame F 50  is also the smallest structural element J and the elementary cube in the sectional cubic block of the present invention.  
         [0062]    Please refer to FIGS. 22, 25 and  26 . The second structural element G can be similarly disassembled into four elementary frames, which are denoted as G 10 , G 20 , G 30  and G 40  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame G 40  is also the smallest structural element J and the elementary cube in the sectional cubic block of the present invention.  
         [0063]    Please refer to FIGS. 22, 27 and  28 . The third structural element H can be similarly disassembled into three elementary frames, which are denoted as H 10 , H 20  and H 30  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame H 30  is also the smallest structural element J and the elementary cube in the sectional cubic block of the present invention.  
         [0064]    Please refer to FIGS. 22, 29 and  30 . The fourth structural element I can be similarly disassembled into two elementary frames, which are denoted as I 10  and I 20  from the outer or larger one to the inner or smaller one. Wherein, the smaller elementary frame I 20  is also the smallest structural element J and the elementary cube in the sectional cubic block of the present invention.  
         [0065]    As can be seen from FIGS. 24, 26,  28  and  30 , any one of the elementary frames F 10 , F 20 , F 30 , F 40 , G 10 , G 20 , G 30 , H 10 , H 20  and I 10  that are not the elementary cubes may be included in a virtual cubic solid and constitutes two adjacent edges of each side of the virtual cubic solid. That is, each of the elementary frames F 10 , F 20 , F 30 , F 40 , G 10 , G 20 , G 30 , H 10 , H 20  and I 10  is an integral frame including three continued right-angled parts that are respectively included in three planes extended in the directions of x, y and z axes. The elementary frames F 10 , F 20 , F 30 , F 40 , G 10 , G 20 , G 30 , H 10 , H 20  and I 10  also sequentially define inner spaces F 11 , F 21 , F 32 , F 41 , G 11 , G 21 , G 31 , H 11 , H 21  and I 11 . Please note elementary frames F 10 , F 20 , F 30 , G 10 , G 20  and H 10  also define an opening each, via which inner spaces F 11 , F 21 , F 31 , G 11 , G 21  and H 11  communicate an inner side with an outer side of the elementary frames F 10 , F 20 , F 30 , G 10 , G 20  and H 10 , respectively.  
         [0066]    The integral elementary frames F 10 , F 20 , F 30 , F 40 , G 10 , G 20 , G 30 , H 10 , H 20  and I 10  are provided on their respective three right-angled parts with unit marks using the smallest structural element J as one unit. These unit marks enable children to actually understand the elementary structure and the number of units of such elementary structure included in a three-dimensional structure, guide children to correctly read and discuss different mathematical units and numbers, and train children to precisely describe the shape of a three-dimensional structure.  
         [0067]    [0067]FIG. 31 shows a sectional cubic block according to a third embodiment of the present invention. This sectional cubic block is also formed from a plurality of structural elements. Each structural element forms a layer of the sectional cubic block. The number of the structural elements may be freely increased or decreased. In the illustrated sectional cubic block of FIG. 31, only five structural elements are included for the convenience of explanation of the present invention.  
         [0068]    The sectional cubic block of FIG. 31 is assembled from five layers or five structural elements K, L, M, N and O that are proportionally reduced in dimensions. FIG. 32 is an exploded perspective view showing these five structural elements. As can be seen from FIG. 32, the structural element K is the largest and the first one of these five structural elements, and the structural element O is the smallest and the fifth one and forms an elementary cube in the sectional cubic block of the present invention. The first, the second, the third, and the fourth structural elements K, L, M and N all include three plane walls (K 01 , K 02 , K 03 ), (L 01 , L 02 , L 03 ), (M 01 , M 02 , M 03 ), and (N 01 , N 02 , N 03 ) that extend in three different directions of x, y and z axes and therefore define an inner space K 04 , L 04 , M 04  and N 04 , respectively, for the structural elements K, L, M and N. The structural elements L, M, N and O could be sequentially received in the inner spaces K 04 , L 04 , M 04  and N 04  and thereby form a complete sectional cubic block of the present invention as shown in FIG. 31. FIGS. 33, 35,  37  and  39  sequentially show the structural elements K, L, M and N, viewed from an outer side of these elements. All these structural elements K, L, M and N could be further disassembled into several elementary frames. FIG. 34 shows the first structural element K is disassembled into five elementary frames, which are denoted as K 10 , K 20 , K 30 , K 40  and K 50  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame K 50  is also the smallest structural element O and the elementary cube in the sectional cubic block of the present invention.  
         [0069]    Please refer to FIGS. 32, 35 and  36 . The second structural element L can be similarly disassembled into four elementary frames, which are denoted as L 10 , L 20 , L 30  and L 40  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame L 40  is also the smallest structural element O and the elementary cube in the sectional cubic block of the present invention.  
         [0070]    Please refer to FIGS. 32, 37 and  38 . The third structural element M can be similarly disassembled into three elementary frames, which are denoted as M 10 , M 20  and M 30  from the outmost or largest one to the innermost or smallest one. Wherein, the smallest elementary frame M 30  is also the smallest structural element O and the elementary cube in the sectional cubic block of the present invention.  
         [0071]    Please refer to FIGS. 32, 39 and  40 . The fourth structural element N can be similarly disassembled into two elementary frames, which are denoted as N 10  and N 20  from the outer or larger one to the inner or smaller one. Wherein, the smaller elementary frame N 20  is also the smallest structural element O and the elementary cube in the sectional cubic block of the present invention.  
         [0072]    As can be seen from FIGS. 34, 36,  38  and  40 , any one of the elementary frames K 10 , K 20 , K 30 , K 40 , L 10 , L 20 , L 30 , M 10 , M 20  and N 10  that are not the elementary cubes may be included in a virtual cubic solid and constitutes two adjacent edges of each side of the virtual cubic solid. That is, each of the elementary frames K 10 , K 20 , K 30 , K 40 , L 10 , L 20 , L 30 , M 10 , M 20  and N 10  is an integral frame including three continued right-angled parts that are respectively included in three planes extended in the directions of x, y and z axes. The elementary frames K 10 , K 20 , K 30 , K 40 , L 10 , L 20 , L 30 , M 10 , M 20  and N 10  also sequentially define inner spaces K 11 , K 21 , K 32 , K 41 , L 11 , L 21 , L 31 , M 11 , M 21  and N 11 . Please note elementary frames K 10 , K 20 , K 30 , L 10 , L 20  and M 10  also define an opening each, via which inner spaces K 11 , K 21 , K 31 , L 11 , L 21  and M 11  communicate an inner side with an outer side of the elementary frames K 10 , K 20 , K 30 , L 10 , L 20  and M 10 , respectively.  
         [0073]    The following are some advantages of the sectional cubic block of the present invention:  
         [0074]    1. All the elementary frames constituting the sectional cubic block of the present invention have fully symmetrical shapes and therefore very stable center of gravity that facilitates easy and balanced stacking of these elementary frames. Children may freely assemble the elementary frames into many changeful, firm and stable shapes completely according to their imagination. The sectional cubic block of the present invention therefore allows children to extend their potential of creation.  
         [0075]    2. The elementary frames of the sectional cubic block of the present invention are proportionally increased or reduced in dimensions and are spatially associable, so that they could be regularly assembled into a cubic solid. Children could be educated through these proportional elementary frames about the concept of permutations in three-dimensional space and the effect that could be achieved through such spatial permutations. Children could be trained to do mathematical operation and quickly read out the number of components included in a three-dimensional structure.  
         [0076]    3. The elementary frames of the sectional cubic block of the present invention have cute and symmetrical shapes and could be differently connected to form many fantastic and unexpected shapes showing multi-layered and contoured appearances that attract both children and adults.  
         [0077]    4. Many surprisingly interesting shapes from simple to very complicate structures could be created from the elementary frames of the present invention in the course of stacking them. The present invention is therefore suitable for people of all ages.  
         [0078]    The present invention has been described with some preferred embodiments thereof and the illustrated embodiments have only five layers for the convenience of explanation. It is understood that the sectional cubic block of the present invention may have increased or decreased number of layers, and the size thereof may be proportionally enlarged or reduced. It is also understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.