the building toy block arrangement of fig1 and 2 is seen to comprise , a mega blok toy block 1 over which is mounted a mega plus + followed by a duplo block 5 coupled to a lego block 7 ; the latter two blocks 5 , 7 , being of the type disclosed in the aforesaid u . s . patents . the mega blok toy block 1 has a large square hollow box - like base 8 defined by sidewalls , a top wall 9 and an open end facing the top wall 9 . four like . i . e . identical , primary cylindrical coupling plugs 11 project upwardly from the top wall 9 and their longitudinal axes are disposed at the four corners of a square . a secondary cylindrical coupling plug 13 projects down from the top wall 9 into the base 8 , being coaxial with the center of the square of the plugs 11 . the mega plus + block 3 has a large hollow box - like square base 15 , of the same size as base 8 of block 1 ; the base 15 being defined by sidewalls , a top wall 17 and an open end facing the top wall 17 . it has four groups , of four primary coupling elements 19 , each element being solid with and projecting upwardly from the top wall 17 , being further disposed around a central axis normal to wall 17 . each element 19 has a constant cross section with an outer configuration in the form of a quadrilateral figure formed by consecutive concave walls 27 , 29 located respectively outwardly and inwardly with respect to the abovementioned central axis , as best seen in fig9 which , however , shows a mega plus + block having only two groups of four elements 19 . as shown also , the inner concave walls 29 of each group of elements 19 define four arcs of a common circle to which reference is made hereinafter . it will further be noted that pairs of adjacent outer concave walls 27 create together lengthwise ridges 31 normal to the top wall 17 . additionally and as best seen in fig8 two inner walls 21 , 23 , at right angle to one another , are provided in the base 15 and divide it into four square chambers 25 . the geometric projections of these inner walls 21 , 23 , symmetrically separate the four groups of coupling elements 19 . the diameter of the four primary plugs 11 of the mega blok 1 is selected for snugly fitting each into one of the four chambers 25 of the mega plus + block . this may necessitate , depending on the thickness of the walls of the base 15 , the presence of lengthwise center ribs 26 . also regarding the mega plus + block , facing concave walls 27 around the center 33 of the block 3 , i . e ., at the center of the four groups of coupling elements 19 , are four arcs of a circle which has the same diameter as that of the secondary coupling plug 13 of the mega blok 1 so that this plug 13 is capable of being gripped between the said four center concave walls , as would be the case in the combination of fig3 . as shown in fig2 the duplo block 5 , which is of the basic or modular type , has a hollow box - like base 35 defined by sidewalls , a top wall 37 and an open end facing the top wall . as a basic duplo block , it has an even number of four primary cylindrical and identical coupling studs 39 projecting upwardly from its top wall ; their longitudinal axes being disposed at the four corners of a square . it also has a secondary cylindrical coupling stud 41 that projects below the top wall 37 within the base 35 , being coaxial with the center of the above said square . the outer diameter of the stud 41 is equal to that of the aforesaid circle formed by the inner concave walls 29 ( fig9 ) in each of the four groups of concave elements 19 so that the secondary stud 41 can be gripped between the primary elements 19 of any one of the groups . finally , the adjacent sidewalls of the duplo base 35 have lengthwise corner ribs 43 as illustrated in fig6 . these ribs are spaced apart a distance suitable for them to slide along the ridges 31 of the elements 19 of the mega all block when the two blocks are coupled . fig4 shows a basic or module type of mega plus + block 42 having only one group of primary coupling elements 19 . its base 44 is rectangular in cross - section with its width being half that of the mega plus + block 3 in fig2 and 3 . in fig5 block 42 is shown coupled , at the top , to a duplo block 5 and their cross - section appears in fig6 . the sidewalls of the base 44 of the mega plus + block 42 is inwardly ribbed in the same manner as one quarter of the base 15 in the mega plus + block 3 of fig8 . a similar rib arrangement also appears within the base 35 of the duplo block 5 in fig5 . the lego block 7 at the top of fig1 and 2 , has a base 45 having a top wall 47 from which project two rows of four primary coupling studs 49 inscribed into three contiguous squares . beneath the top wall 47 and into the base 45 are three cylindrical secondary aligned studs 51 of which the geometrical projections are tangent each to four primary plugs 49 . as known , when coupled to a duplo block , the outer two secondary plugs 51 are inserted in two primary tubular plugs 39 of the duplo block ; the center secondary plug 51 falling in between the plugs 39 . fig1 and 12 refer to a combination of a mega plus + block 53 with a duplo block 55 coupled at its lower end ; the duplo block 55 being detailed at the bottom of fig3 . both are rectangular parallelepipeds . as shown , the base 57 of the mega plus block 53 is half the size of the base 15 of the mega plus block 3 in fig1 and 2 , while the base 59 of the duplo block 55 is twice the size of the base 35 of the duplo block 5 in fig2 . the mega plus + block has two groups of primary elements 31 . the duplo block 55 has two rows of tubular primary coupling elements 39 and three aligned secondary coupling plugs 41 , as shown in fig3 . an inner central wall 61 divides the base 57 of the mega plus + block 53 into two square chambers 63 ; the projection of the wall 61 dividing the elements 31 into two symmetrical groups . as clearly illustrated in fig3 and 12 , there are two groups of four equally spaced tubular primary studs 39 distributed in two rows at the corners of two squares . the construction is such that the two groups are each capable of fitting snugly each into one of the chambers 63 . this may necessitate , depending on the thickness of the walls of the base 57 and of the central wall 61 , the presence of lengthwise corner ribs 65 . as said above , the duplo block 55 has three secondary studs 41 ( fig3 ). the geometrical projections of these studs are each tangent to two pairs of adjacent primary studs 39 . on the other hand , facing inner concave walls 29 ( fig9 ) of the mega plus + block define arcs of three aligned circles of equal diameter , which diameter is also equal to the diameter of the three secondary studs 41 so that the latter may be gripped by the coupling elements 19 forming the arcs of the three aligned circles mentioned above . regarding again the outer dimensions of the bases 8 , 15 and 35 of the mega blok , mega plus + and duplo blocks , as in fig1 and 2 , it is seen that , while all bases are square in cross - section , the width and height of the mega blok and mega plus + bases 8 , 15 , are equal and the width and height of the duplo base 35 are equal to half those of the bases 8 , 15 . in the combination of fig3 the cross - section and size of the bases 8 , 15 , of the mega blok and mega plus + blocks are again the same but the base 59 of the duplo block 55 is rectangular in cross - section . also , while its width is the same as that of the bases 8 , 15 , its depth and height are only half those of bases 8 , 15 . referring to fig5 and 6 , showing a modular type of duplo block 5 mounted on a modular type of mega plus + block 42 , both are rectangular in cross - section and their width are equal . however , the height of the duplo block base 35 is only half that of the mega plus + block base 44 . the bottom view of the mega plus + block 53 in fig1 shows its primary coupling elements 19 to be hollow , as at 67 .
there is disclosed a construction toy kit including small and large blocks having a hollow open ended box - like base with primary cylindrical outer couplers and inner cylindrical couplers within the base . the size and configuration of these blocks do not allow them to be coupled directly together and the kit includes intermediate blocks capable of so doing .