as said above , fig1 and 2 illustrate a known brick - like assembly unit . it is shown to comprise a hollow rectangular parallelepiped body 1 made of four consecutive walls 3 , 5 , 7 and 9 , adjacent edges of these walls defining an open end 11 while a fifth wall 13 , normal to walls 3 , 5 , 7 and 9 , closes the end of body 1 opposite the open end 11 . fifth wall 13 , in fig1 and 2 , is provided with four symmetrically disposed parallel spaced connection plugs 15 . plugs 15 are cylindrical bodies having their upper ends chamfered at 17 . they are positioned , on the top wall 13 , so as to leave a narrow ledge area 19 of which the width is essentially equal to the thickness of the walls 3 to 9 so that the connecting plugs 15 define confining wall means suitable for the plugs 15 to fit snugly into the hollow chamber of a like assembly unit , as is known . a first additional building unit , made according to the invention , is shown at 23 in fig3 . it is seen to be made of two parts 23 , 25 , of equal constant rectangular cross - sections solidly joined together along a common end , which may be a solid wall 27 , and at essentially 45 °. the end of part 23 opposite the common end 27 is a solid wall 29 from which connection plugs 15 project . that part 23 may be completely solid although it will usually be hollowed out . the other part 25 is hollow and its end 31 is open for the snug reception of connection plugs of another assembly unit . an assembly stabilizing elongated member 33 , which may be tubular , projects from the solid wall 27 centrally into the hollow part 25 , stabilizing member 33 being round in cross - section and being sized so that it may fit in the nip 35 ( fig2 ) tangentially between two connection plugs 15 of another assembly unit . likewise , when the hollow part 25 is made to sit squarely over top wall 9 of the unit one of fig2 the stabilizing member 33 becomes tangent to all four plugs 15 and , in both situations , it serves to prevent wobbling between interconnected building units . a second additional unit 36 according to the invention is shown in fig4 and 5 . this unit is also made of two parts 37 , 39 , wherein part 37 may either be solid or preferably hollow . both parts 37 and 39 are of equal constant cross - section and means are provided to join them at a common end for relative pivotal movement about an axis which is normal to and centrally of this rectangular cross - section . part 39 has a solid closing wall 41 at the common end between parts 37 and 39 . as in the additional unit shown in fig4 a stabilizing member 43 depends from the solid wall 41 and defines a bore 45 having a bottom wall merging with the common end solid wall 41 . this bottom wall , as shown , is centrally pierced to form a locking aperture 47 . the pivot means aforesaid , between parts 37 and 39 , is shown to comprise a bulb element 49 , provided at the end of a tubular rod 51 solid , at one end , with part 37 , the bulb element 49 projecting past the common end wall 41 . it is seen to be formed of a narrow portion extending freely through the locking aperture 47 and of a wide portion received in the bore 45 and bearing freely against the bore bottom wall . as best illustrated in fig5 the wide portion of the bulb 49 is longitudinally slit at 53 to thus define two resilient legs 55 to permit insertion of the bulb element 49 into the bore 45 through the locking aperture 47 . this construction makes it possible to hold part 37 firmly over wall 41 while allowing relative rotation about a longitudinal axis common to both parts 37 and 39 . the third additional unit 57 according to the invention is shown in fig6 and 7 . it is seen to comprise four consecutive walls 59 , 61 , 63 and 65 defining a hollow body of constant rectangular cross - section open at both ends 67 , 69 , for the snug reception of connecting plugs 15 of another assembly unit , as explained earlier with respect to the other additional units . the connecting plugs 15 of this third additional unit project from only one wall 65 of the four consecutive walls . this third unit further comprises a solid partition wall 71 within and centrally of the hollow body defined by the consecutive walls 59 - 65 and perpendicularly thereto . coaxial assembly stabilizing elongated members 73 , 75 , which may be hollow , project from the center of the petition wall 71 toward the open ends 67 , 69 , and serve the same purpose as the stabilizing members 33 and 43 of the first and second additional units aforedescribed . fig8 shows two additional units 21 of the first type about to be interconnected . fig9 shows one type of construction which uses exclusively the three additional units 21 , 57 and 36 of the invention . unit 36 particularly illustrates how an upper part of a construction ( not shown ) may be pivoted about a lower part serving as a base . the arrangement shown in fig1 illustrates a construction using both conventional units 1 mounted on a base made up of additional units 21 , 57 , and supporting an upper structure made up of additional units 57 and 21 of the invention .
a construction toy assembly includes brick - like units of which one wall only has connecting plugs . one unit is made of two parts solid with one another and extending at 45 ° therebetween ; another unit is also formed of two parts but the parts can pivot with respect to one another about a common axis and still another unit is in the form of a hollow open - ended tube which is rectangular in cross - section .