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This application is a continuation-in-part of International Patent Application PCT/U503/28279, filed Sep. 9, 2003, and is a continuation-in-part of U.S. patent application Ser. No. 10/418,563, filed Apr. 17, 2003, now U.S. Pat. No. 6,948,282, which claims priority to U.S. Provisional Patent Application No. 60/438,960 filed Jan. 9, 2003. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to a building block for building a free-standing mortarless wall, particularly to such a building block having an interlock and flat surfaces extending outwardly from the interlock, and specifically to such an interlocking building block having at least one core and further having a secondary or end core portion formed on each end of the building block for being seated upon an interlock of an adjoining lower building block. 
   Dragsters have rear wheel mounted slicks, which are wide flat tires with little or no tread. The relatively great amount of surface area better grabs the road for acceleration. Treads decrease the amount of grab and therefore decrease the amount of acceleration. 
   WWII style jeeps run on relatively skinny tires. The skinnier the tire, the more pressure per square inch on the portion of the tire digging down into the mud or sand, and the better the traction. 
   The lessons of flatness and pressure, well-known in the automobile arts, have been overlooked by building block manufacturers. A great number of building blocks have recesses or grooves for performing a various number of functions. Likewise, a great number of building blocks have extensions or projections or nubs for performing a various number of functions. Often, if not a majority of the time, these recesses or extensions of the building block necessarily transfer the load bearing function to other portions of the building block. Such a transfer may place an undue amount of stress in such other portions of the building block or may imbalance the block or a wall formed by such blocks. 
   With appreciation for the lessons of flatness and pressure, a mortarless and free-standing wall according to the present invention may be built having a great amount of stability with or without internal piping. 
   SUMMARY OF THE INVENTION 
   A feature of the present invention is the provision in a building block having at least one core and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of an interlock protruding from a load bearing face of the building block and forming at least a portion of the periphery of the core for reception in a secondary core portion of an adjacent building block placed at an adjoining level. 
   Another feature of the present invention is the provision in a building block having at least one core and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of an interlock protruding from a load bearing face of the building block and forming at least a portion of the periphery of the core for reception in a secondary core portion of an adjacent building block placed at an adjoining level, and of the interlock being arcuate and endless and running about a perimeter of the core. 
   Another feature of the present invention is the provision in a building block having at least one core and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of an interlock protruding from a load bearing face of the building block and forming at least a portion of the periphery of the core for reception in a secondary core portion of an adjacent building block placed at an adjoining level, of first and second load bearing faces of the building block being substantially flat without taking into account the interlock, and of the first and second load bearing faces being parallel. 
   Another feature of the present invention is the provision in a building block having at least one core and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of an interlock protruding from a load bearing face of the building block and forming at least a portion of the periphery of the core for reception in a secondary core portion of an adjacent building block placed at an adjoining level, and of the interlock having a splitter wedge such that first and second spaced apart interlocking segments are formed. 
   Another feature of the present invention is the provision in a building block having at least one core and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of an interlock protruding from a load bearing face of the building block and forming at least a portion of the periphery of the core for reception in a secondary core portion of an adjacent building block placed at an adjoining level, and of two opposite sides of the building block being textured such that the two opposite sides are aesthetic. 
   Another feature of the present invention is the provision in a building block having a set of three cores and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of interlocks protruding from a load bearing face of the building block and forming at least a portion of the periphery of a respective two of the cores for reception in respective secondary core portions of adjacent building blocks placed at an adjoining level. 
   Another feature of the present invention is the provision in a building block having a set of three cores and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of interlocks protruding from a load bearing face of the building block and forming at least a portion of the periphery of a respective two of the cores for reception in respective secondary core portions of adjacent building blocks placed at an adjoining level, and of a splitter wedge forming a portion of one core to provide an aid for splitting the block in the field. 
   Another feature of the present invention is the provision in a building block having a set of three cores and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of interlocks protruding from a load bearing face of the building block and forming at least a portion of the periphery of a respective two of the cores for reception in respective secondary core portions of adjacent building blocks placed at an adjoining level, and of a splitter wedge cutting across an interlock to provide an aid for splitting the block in the field. 
   Another feature of the present invention is the provision in a building block having a set of three cores and a pair of secondary or end core portions that form secondary cores with adjacent building blocks, of interlocks protruding from a load bearing face of the building block and forming at least a portion of the periphery of a respective two of the cores for reception in respective secondary core portions of adjacent building blocks placed at an adjoining level, and of the two cores being of different size, one sufficiently small so as to exclude the seating of an interlock of a potentially adjoining building block, and one sufficiently large to as to seat an interlock of an adjoining building block. 
   Another feature of the present invention is the provision in a building block having a set of two cores and a secondary or end core portion in one end of the building block, of the two cores being of different size, one sufficiently small so as to exclude the seating of an interlock of a potentially adjoining building block, and one sufficiently large to as to seat an interlock of an adjoining building block. 
   Another feature of the present invention is the provision in a building block having mating interlocking portions comprising cores and protruding interlocks receivable in the cores, the blocks being configured so that adjacent ends of a pair of blocks in a course of a wall together define an interlock portion that interlocks with a mating interlock portion carried by a block in an adjacent course of blocks. 
   Another feature of the present invention is the provision in a building block having mating interlocking portions comprising cores and protruding interlocks receivable in the cores, the blocks being configured so that adjacent ends of a pair of blocks in a course of a wall together define a protruding interlock portion that interlocks with a mating interlock core portion carried by a block in an adjacent course of blocks. 
   Another feature of the present invention is the provision in a building block having mating interlocking portions comprising cores and protruding interlocks receivable in the cores, the blocks being configured so that adjacent ends of a pair of blocks in a course of a wall together define a core interlock portion that interlocks with a mating protruding interlock core portion carried by a block in an adjacent course of blocks. 
   An advantage of the present invention is stability. The present building blocks can form a free standing mortarless wall having great stability without piping. One feature contributing to this advantage is the interlock. Another feature contributing to this advantage is the flatness of the upper and lower load bearing faces that provides load to be transmitted evenly over a maximum amount of surface area. 
   Another advantage of the present invention is that piping may be incorporated into the free standing mortarless wall. As such a wall is built, cores are naturally aligned to permit the placement of pipes therein. 
   Another advantage of the present invention is that the present interlocks may be seated in some cores and not in other cores. Such a natural selection and exclusion provides for a mistake free and self-aligning wall. 
   Another advantage is that the building block may be used as the basis for a unique wall. For example, the interlock and its mating secondary or end core portion are structured to permit building blocks, of one shape, to form either a straight wall or a curved wall. Also, ends of the building block are oblique such that a set of basic building blocks having one shape can form a straight wall or a curved or undulating wall. Further, the interlock and its mating secondary core portion may be rotationally adjusted and still interlock, such as when the homeowner saws off or splits off the end of the building block to make her own unique angle or curvature. Moreover, the secondary core portion is formed relatively deeply in the building block such that a recess still remains in the building block for the interlock when a home owner saws off such end of the building block. 
   Another advantage is that a free standing wall built by a set of the present building blocks is safe with or without glue, is safe with or without posts, is safe while being built, is safe after completion, and is safe for a great number of years. For instance, the present building block has inner cores and secondary (or end) core portions so as to be hollow and relatively light and easy to handle for the do-it-yourself home owner. Further, the interlocks minimize movement of just laid down building blocks so as to minimize toppling of walls under construction. Still further, some interlocks are have splitter wedges to permit field modification. Also, posts may be inserted through any of the cores or need not be inserted at all. 
   Another advantage is the ability to build in structural stability achieved when serpentine or curved walls are constructed. 
   Another advantage is the ability to build in structural stability achieved when zig zag type walls are constructed. 
   Another advantage is the ability to achieve rigidity with or without piping. When used, a lower portion of piping is driven into the ground and an upper portion of the piping confronts internal cores, namely the cores of interlocks. 
   Another advantage is that the free standing wall can be relatively easily removed by a subsequent home owner. The free standing wall built by a set of the present building blocks does not require reinforcing rods, posts, glue, or relatively deep holes dug into the ground. Further, the present building block is relatively hollow to thereby minimize mass that must be removed by a home owner having different tastes. 
   Another advantage is that the present building block is relatively inexpensive to manufacture. 
   Other and further features and advantages of the present invention will become apparent to those skilled in the art upon a review of the accompanying specification and drawings. 

   
     IN THE DRAWINGS 
       FIG. 1  is a perspective view of the angle block of the present invention having the endless interlock. 
       FIG. 2A  is a top view of the angle block of  FIG. 1 . 
       FIG. 2B  is a side view of the angle block of  FIG. 2A . 
       FIG. 2C  is a partially broken away top view similar to that of  FIG. 2A  but showing another embodiment of the angle block. 
       FIG. 2D  is a side view of the angle block of  FIG. 2C . 
       FIG. 3A  is a top view of the angle block of the present invention having a splitter wedge at the interlock. 
       FIG. 3B  is a side view of the angle block of  FIG. 3A . 
       FIG. 4  is a top view of the mold layout for the angle blocks of  FIGS. 2A and 3A . 
       FIG. 5A  is a top view of the stretcher block of the present invention having a pair of endless interlocks. 
       FIG. 5B  is a side view of the stretcher block of  FIG. 5A . 
       FIG. 5C  is a top view similar to that of  FIG. 5A  but showing another embodiment of the stretcher block of the present invention having a pair of core interlocks. 
       FIG. 5D  is a side view of the stretcher block of  FIG. 5C . 
       FIG. 6A  is a top view of the stretcher block of the present invention having a splitter wedge at the central core. 
       FIG. 6B  is a side view of the stretcher block of  FIG. 6A . 
       FIG. 7A  is a top view of the stretcher block of the present invention having a splitter wedge at one of the interlocks. 
       FIG. 7B  is a side view of the stretcher block of  FIG. 7A . 
       FIG. 8  is a top view of a mold layout for the stretcher blocks of  FIGS. 5A ,  6 A and  7 A. 
       FIG. 9A  is a top view of a corner block of the present invention. 
       FIG. 9B  is a side view of the corner block of  FIG. 9A . 
       FIG. 10  is a top view of a mold layout for the corner block of  FIG. 9A . 
       FIG. 11A  is a top view of the cap block of the present invention. 
       FIG. 11B  is a side view of the cap block of  FIG. 11A . 
       FIG. 12  is a top view of a mold layout for the cap block of  FIG. 11A . 
       FIG. 13A  is a top view of a post cap block of the present invention. 
       FIG. 13B  is an end view of the post cap block of  FIG. 13A . 
       FIG. 13C  is a side view of the post cap block of  FIG. 13A . 
       FIG. 14  is a top view of the mold layout for the post cap block of  FIG. 13A . 
       FIG. 15A  is a top view of a straight wall portion utilizing the angle block of  FIG. 2A . 
       FIG. 15B  is a top view of a straight wall portion utilizing the stretcher block of  FIG. 5A . 
       FIG. 16A  is a top view of a curved wall portion utilizing the angle block of  FIG. 2A . 
       FIG. 16B  is a top view of a curved wall portion utilizing the angle block of  FIG. 2A , a portion of the angle block of  FIG. 3A , the stretcher block of  FIG. 5A , and the corner block of  FIG. 9A . 
       FIG. 17A  shows a portion of a corner of a wall formed by corner blocks of  FIGS. 9A and 9B . 
       FIG. 17B  shows a masonry post formed by corner blocks of  FIGS. 9A and 9B . 
       FIG. 18A  shows a portion of the wall utilizing piping for resistance to over-turning of the wall. 
       FIG. 18B  shows how a random look can be provided to a wall utilizing blocks of the present invention. 
       FIG. 19A  is a top view of a portion of a serpentine wall having a relatively great amount of stability. 
       FIG. 19B  is a top view of a portion of another type of serpentine or zig zag like wall having a great amount of stability. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In accordance with a preferred embodiment of the present invention, a set of building blocks for one or more portions of a mortarless free standing wall having two textured opposing sides includes an angle block  10  shown in  FIGS. 1 ,  2 A,  2 B,  2 C, and  2 D, an angle block  12  having a splitter wedge and shown in  FIGS. 3A and 3B , a stretcher block or double unit block  14  shown in  FIGS. 5A ,  5 B,  5 C, and  5 D, a stretcher block or double unit block  16  having a splitter wedge at the central core and shown in  FIGS. 6A and 6B , a stretcher block or double unit block  18  having a splitter wedge at one interlock and shown in  FIGS. 7A and 7B , a corner block  20  shown in  FIGS. 9A and 9B , a cap block  22  shown in  FIGS. 11A and 11B , and a post cap block  24  shown in  FIGS. 13A and 13B . 
   Angle Block  10   
   As shown in  FIGS. 1 ,  2 A and  2 B, angle block  10  generally includes a first load bearing face  30 , a second load bearing face  32 , a first end  34 , a second end  36 , a first side  38 , and a second side  40 . Angle block  10  further includes a first or central or inner or primary core  42  defined by a cylindrical or core wall  44 , a secondary or end core portion or end arcuate recess or seat  46  defined by a cylindrical or core wall  48 , a secondary or end core portion or end arcuate recess or seat  50  defined by a cylindrical or core wall  52 , and an endless interlock  54  about a perimeter of the primary core  42 . Angle block  10  still further includes four corner faces or chamfers  56 ,  58 ,  60 , and  62 . 
   As shown in  FIGS. 2A and 2B , first loading bearing face  30  is disposed opposite of second load bearing face  32 . Each of the load bearing faces  30 ,  32  is disposed in a plane that is parallel to the plane of the other load bearing face. Each of the load bearing faces  30 ,  32  is transverse to or lies at a crosswise direction relative to ends  34 ,  36  and sides  38 ,  40 . Generally, each of the load bearing faces  30 ,  32  is trapezoidal. Specifically, each of the load bearing faces  30 ,  32  is bounded by a set of 12 edges formed by the corner faces or chamfers  56 ,  58 ,  60  and  62 , the ends  34 ,  36  having the secondary walls  48 ,  52 , and the sides  38 ,  40 . 
   Primary core  42  is formed centrally in angle block  10  and extends to and between each of the load bearing faces  30 ,  32 . An axis running centrally through primary core  42  is equidistant from side  38  and side  40  and is further equidistant from a midpoint on end  34  and a midpoint on end  36 . 
   Primary core  42  is an internal core. That is, primary core  42  is spaced from each of the first and second sides  38 ,  40  and each of the first and second ends  34 ,  36 . 
   The diameter or size of the primary core  42  in combination with the size of the secondary core portions  46 ,  50  is sufficiently large so as to minimize the weight or mass of angle block  10  and sufficiently small so as to provide sufficient mass and strength to angle block  10  such that a set of angle blocks  10 , alone or in combination with other building blocks, can make up a free standing wall. 
   Endless interlock  54  runs about a perimeter of the primary core  42  on first load bearing face  12  so as to be curved or arcuately shaped so as to cooperate with one of a secondary core wall of an adjacent building block, such as secondary core walls  48 ,  52  of an adjacent angle block  10 , that is placed at an immediately adjoining level. Such a curved or arcuate shape, or more preferably a circular shape, and most preferably an endless circular shape, permits rotational adjustment of angle block  10  relative to another building block while maintaining an interlock between the blocks. Building blocks interlock when two adjacent blocks at the same level are placed end to end, preferably without glue, such that confronting secondary core portions form a secondary core and thus a receptor for endless interlock  54  of a building block, such as angle block  10 , at an immediately adjoining level. 
   It can be seen from a section view that endless interlock  54  includes a cylindrical wall surface portion  70  running parallel and in line with cylindrical wall  44 , a top endless surface portion  72  running outwardly from cylindrical wall surface portion  70  and extending generally parallel to load bearing face  30 , and a tapering or beveled endless surface  74  tapering from top endless surface portion  72  to load bearing face  30 . Again, the seat for endless interlock  54  is a secondary core formed by two secondary core portions. Such a secondary core or seat includes secondary core portion walls, such as walls  48 ,  52 , that run normal to a second load bearing face, such as face  32 . The tapering or beveled endless surface  74  aids in aligning endless interlock  54  with the walls of the secondary core portions. The radius of endless interlock  54 , measured at the intersection between tapering or beveled endless surface  74  and load bearing face  30 , is substantially equal to, and preferably slightly less than, the radius of secondary core walls, such as secondary core walls  48  and  52 . Endless interlock  54  is molded or formed at the same time as angle block  10  such that endless interlock  54  is one-piece with and integral with angle block  10 . 
   End  34  is disposed opposite end  36 . End  34  includes a first generally flat surface or face  80  and a second generally flat surface or face  82 , with each of the flat surfaces  80 ,  82  running normal to load bearing faces  30 ,  32 . Secondary core portion  46  is formed intermediate the flat surfaces  80 ,  82 . Flat surfaces  80 ,  82  lie in a plane that is oblique to each of sides  38 ,  40 . End  36  includes a first generally flat portion  84  and a second generally flat surface  86 , with each of the flat surfaces  84 ,  86  running normal to load bearing faces  30 ,  32 . Secondary core portion  50  is formed between the flat surfaces  84  and  86 . Flat surfaces  84 ,  86  lie in a plane that is oblique to each of sides  38 ,  40 . The plane in which flat portions  80 ,  82  are disposed is oblique relative to the plane in which flat portions  84 ,  86  are disposed. Each of the flat portions  80 ,  82 ,  84 ,  86  is transverse to or lies at a crosswise direction relative to faces  30 ,  32  and sides  38 ,  40 . By virtue of the mutually inclining ends  36 ,  38 , a set of angle blocks  10 , alone or in combination with other blocks, can form either a curved row of blocks or a straight row of blocks or a combination of both so as to form, for example, an undulating or serpentine row of blocks. As shown in  FIG. 16A , a continuously curving row of blocks is formed when each of the sides  38  confronts or is aligned with each of the other sides  38 . As shown in  FIG. 15A , a straight row of blocks is formed when blocks are placed front-to-back such that side  38  of one block runs into side  40  of the immediately adjacent block that in turn runs into side  38  of the subsequent immediately adjacent block, with such a pattern continuing for a desired length. An undulating row of blocks may be formed by some combination of curved and straight row portions. 
   Sides  38 ,  40  of angle block  10  are disposed opposite of each other. Each of the sides  38 ,  40  is disposed generally in a plane that is generally parallel to the plane of the other side. Each of the sides  38 ,  40  is transverse to or lies at a crosswise direction relative to load bearing faces  30 ,  32  and ends  34 ,  36 . Sides  38 ,  40  form the exterior vertical faces of the free standing wall. Sides  38 ,  40  are preferably textured so as to form a double-sided textured wall. 
   A second embodiment of an angle block  10  is shown in  FIGS. 2C and 2D . This embodiment also includes a first load bearing face  30 , a second load bearing face  32 , a first end  34 , a second end  36 , a first side  38 , and a second side  40 , also shown in the embodiment of angle block  10  shown in  FIGS. 2A and 2B . 
   The embodiment shown in  FIGS. 2C and 2D  is different in that the structure of the primary core  42  shown in  FIGS. 2A and 2B  is divided to form two core segments  360  that are placed in the position of the secondary core, while the secondary core elements  46 ,  50 , are combined to form one core structure  370  and placed in the position of the primary core. 
   The interlock portion of any embodiment of the angle block  10  that is entirely contained on a single block may be referred to as a full interlock. The interlock portion on the end of a block which cooperates with another interlock portion at the end of another block may be referred to as a half interlock. 
   The embodiment of the angle block  10  shown in  FIGS. 2C and 2D  may be used in the same fashion as the embodiment shown in  FIGS. 2A and 2B  to form either a curved row of blocks or a straight row of blocks or a combination of both so as to form, for example, an undulating or serpentine row of blocks. The walls shown in  FIGS. 15A and 16A  are formed in the same fashion from the angle blocks of  FIGS. 2C and 2D  as previously described with respect to the angle blocks shown in  FIGS. 2A and 2B . The details of construction shown with respect to the angle blocks in  FIGS. 2A ,  2 B,  2 C, and  2 D are merely exemplary embodiments of the angle block  10 , and should not be interpreted as limiting the scope of the claims appended to this application. 
   Angle Block  12  Having a Splitter Wedge 
   As shown in  FIGS. 3A and 3B , angle block  12  is identical to angle block  10  with the exception of a splitter space or score or recess  90  that cuts across the interlock so as to form a discontinuous interlock  92  having interlock segments  94 . Each of the interlock segments  94  has a pair of ends or end faces  96  that are spaced from the ends or end faces  96  of the other interlocking segment  94  so as to therebetween form the splitter space  90 . Space  90  runs to and between each of the load bearing faces  30 ,  32 . Space  90  opens to and communicates with the inner core  42 . 
   Space  90  is a marker or aid for splitting angle block  12 , such as in the field, into at least two portions along a plane  98  that runs substantially normal to faces  30 ,  32 . Once split, such as with a chisel or other wedged-shaped tool or such as with a saw, right hand straight and left hand straight blocks are formed. Portion or block  100  forms a left hand straight building block and portion or block  102  forms a right hand straight building block such that each of portions  100 ,  102  have a face formed along plane  98  that is normal to its respective sides  38  and  40  and oblique to its respective surfaces  80 ,  82  and  84 ,  86 . 
   Angle block  12  does not require field modification. If available, angle block  10  with the endless interlock  54  is preferred. However, where angle block  10  is not available, angle block  12  may be substituted for the angle block  10 . The core portions of angle block  12  may also be reversed as shown with respect to the embodiment of angle block  10  shown in  FIGS. 2C and 2D . An embodiment of angle block  12  so constructed would have the splitter wedge  90  disposed proximate to the primary core portion, which in this embodiment of the angle block  12  would not include the interlock which projects upward from the load bearing surface of the angle block  12 . 
   Mold Layout for Angle Blocks  10  and  12   
   As shown in  FIG. 4 , a preferred way of forming a texture or a rough masonry face on sides  38 ,  40  is by splitting blocks molded back to back, such as in a split-face machine. For example, a mold box  103  may be set up such that sides  38  of two different blocks  10  are back to back and such that sides  40  of two different blocks  10  are back to back. Then the blocks  10  are split along sides  38  and sides  40  to create the texture. 
   In  FIG. 4 , mold portions are indicated by reference number  104  and confront, for example, at least load bearing surfaces  30 ,  32 , first end  34  including wall  48  and surfaces  80 ,  82 , second end  36  including wall  52  and surfaces  84  and  86 , cylindrical wall  44 , cylindrical wall portion  70  of interlock  54 , top surface  72  of interlock  54 , tapering or beveled surface  74 , chamfers  56 ,  58 ,  60 , and  62 , and, where interlock segments  94  are formed, ends or end faces  96  and the portions of load bearing surface  30  that run into and between interlock segments  94 . 
   In  FIG. 4 , excess masonry portions are indicated by reference numbers  106  and are split from their respective faces  38  or  40 . 
   Stretcher Block or Double Unit Block  14   
   Stretcher or double unit block  14  is shown in  FIGS. 5A ,  5 B,  5 C, and  5 D. Double unit block  14  includes a first load bearing face  110 , a second load bearing face  112 , a first end  114 , a second end  116 , a first side  118 , and a second side  120 . 
   Stretcher block  14  as shown in  FIGS. 5A and 5B  further includes a central or relatively large second inner core  122  defined by a cylindrical or core wall  124  and, on either side of the relatively large second inner core  122 , a pair of relatively small inner first cores  126 ,  128  defined by respective cylindrical or core walls  130 ,  132 . 
   Stretcher block  14  further includes a secondary or end core portion or end arcuate recess or seat  134  defined by a cylindrical or core wall  136  and a secondary or end core portion or end arcuate recess or seat  138  defined by a cylindrical or core wall  140 . 
   Stretcher block  14  further includes an endless interlock  142  about a perimeter of relatively small inner core  126  and an endless interlock  144  about a perimeter of relatively small inner core  128 . 
   Stretcher block  14  further includes four corner faces or chamfers  146 ,  148 ,  150  and  152 . 
   First loading bearing face  110  is disposed opposite of second load bearing face  112 . Each of the load bearing faces  110 ,  112  is disposed in a plane that is parallel to the plane of the other load bearing face. Each of the load bearing faces  110 ,  112  is transverse to or lies at a crosswise direction relative to ends  114 ,  116 . Generally, each of the load bearing faces  110 ,  112  is a parallelogram. Specifically, each of the load bearing faces  110 ,  112  is bounded by a set of 12 edges formed by the corner faces or chamfers  146 ,  148 ,  150 , and  152 , the ends  114 ,  116  having the secondary walls or recesses  136 ,  138 , and the sides  118 ,  120 . 
   Central core  122  is formed centrally in stretcher block  14  and extends to and between each of the load bearing faces  110 ,  112 . An axis running centrally through central core  122  is equidistant from side  118  and side  120  and is further equidistant from a midpoint on end  114  and a midpoint on end  116 . 
   The diameter or size of the central core  122 , in combination with the diameter or size of relatively small inner cores  126 ,  128 , and further in combination with the diameter or size of secondary core portions  134 ,  138 , is sufficiently large so as to minimize the weight or mass of stretcher block  14  and sufficiently small so as to provide sufficient mass and strength to stretcher block  14  such that a set of stretcher blocks  14 , alone or in combination with other building blocks, can make up a free standing wall. 
   Each of cores  122 ,  126  and  128  is an inner core. That is, each of cores  122 ,  126 ,  128  is spaced from each of the first and second sides  118 ,  120  and each of cores  122 ,  126  and  128  is spaced from each of the ends  114 ,  116 . Each of the cores  122 ,  126  and  128  is spaced from each other. 
   Each of the endless interlocks  144  runs about the perimeter of its respective inner cores  126  and  128  on first load bearing face  110  so as to be curved or arcuately shaped so as to cooperate with one of a secondary core wall of an adjacent building block that is placed at an immediately adjoining level. Such a curved or arcuate shape, or more preferably a circular shape, and most preferably an endless circular shape, permits rotational adjustment between confronting building blocks while maintaining an interlock between the blocks. Stretcher block  14  interlocks with other building blocks when two adjacent blocks are placed end to end, preferably without glue, such that confronting secondary core portions form a secondary core and thus a receptor for one of the endless interlocks  142  at an immediately adjoining level. 
   The endless interlocks  142 ,  144  are identical in shape to endless interlock  54  and include a cylindrical wall surface portion  154  running parallel and in line with its respective cylindrical wall  130 ,  132 , a top endless annular surface portion  156  running outwardly from cylindrical wall surface portion  154  and extending parallel to load bearing face  110 , and a tapering or beveled endless surface  158  tapering from top endless surface portion  156  to first load bearing face  110 . 
   One seat for endless interlocks  142 ,  144  is a secondary core formed by two confronting secondary core portions. Such a secondary core or seat includes secondary core portion walls, such as walls  48  and  52  of angle block  10  or angle block  12  or walls  136  and  140  of stretcher block  14 , stretcher block  16 , and stretcher block  18 , or secondary core portion walls of corner block  20 . These secondary core portion walls run normal to a second load bearing face, such as face  112 . 
   Another seat for endless interlocks  142 ,  144  is the cylindrical wall  124  of primary core  122 . Cylindrical wall  124  of primary core  122  is also a seat for the endless interlock  54  or the discontinuous interlock  92  or any of the interlock segments  94 . 
   Like endless interlock  54 , endless interlocks  142  and  144  include the tapering or beveled endless surface  158  that aids in aligning endless interlocks  142  and  144  with the walls of the secondary core portions. Like endless interlock  54 , each of endless interlocks  142  and  144  have a radius, measured at the intersection between tapering surface  158  and first load bearing face  110 , that is substantially equal to, and preferably slightly less than, the radius of secondary core walls, such as secondary core walls  48 ,  52 ,  136  and  140 . Endless interlocks  142  and  144  are molded or formed at the same time as stretcher block  14  such that endless interlocks  142  and  144  are one-piece and integral with stretcher block  14 . 
   End  114  is disposed opposite end  116 . End  114  includes a first face or generally flat surface  160  and a second face or generally flat surface  162 , with each of the flat surfaces  160 ,  162  running normal to load bearing faces  110 ,  112 . Secondary core portion  134  is formed intermediate the flat surfaces  160 ,  162 . Flat surfaces  160 ,  162  lie in a plane that is oblique to each of sides  118  and  120 . 
   End  116  includes a first face or generally flat surface  164  and a second face or generally flat surface  166 , with each of the flat surfaces  164 ,  166  running normal to load bearing faces  110 ,  112 . Secondary core portion  138  is formed intermediate the flat surfaces  164 ,  166 . Flat surfaces  164 ,  166  lie in a plane that is oblique to each of sides  118  and  120 . 
   The plane in which the pair of flat surfaces  160 ,  162  lies is parallel to the plane in which the pair of flat surfaces  164 ,  166  lies. 
   Each of the flat portions  160 ,  162 ,  164  and  166  is transverse to or lies at a crosswise direction relative to faces  110 ,  112  and sides  116 ,  118 . 
   By virtue of the ends  114 ,  116  having parallel flat surfaces, stretcher blocks  14  placed end to end form a straight line or straight wall portion. In such a straight wall portion, since ends  114 ,  116  have parallel flat surfaces, sides  118  may be aligned with each other or side  118  may be aligned with side  120 . 
   On top of such a straight wall portion, other stretcher blocks  14  may be placed in a staggered relationship such that one of the endless interlocks  142 ,  144  of a lower block  14  is seated in a secondary core formed by two confronting secondary core portions  134  and  138  of the upper straight wall portion and such that the other of the endless interlocks  142 ,  144  of the upper block  14  is seated in a central core  122  of an upper block  14 . Such a staggered relationship forms an interlocking wall of building blocks. 
   Stretcher block  14  may be used in combination with angle blocks  10 ,  12  to provide curves in walls or undulating or serpentine patterns in walls formed by blocks  10 ,  12 ,  14 ,  16 ,  18 , and  20 . 
   Sides  118 ,  120  of stretcher block  14  are disposed opposite of each other. Each of the sides  118 ,  120  is disposed generally in a plane that is generally parallel to the plane of the other side. Each of the sides  118 ,  120  is transverse to or lies at a crosswise direction relative to load bearing faces  110 ,  112  and ends  114 ,  116 . Sides  118 ,  120  form the exterior vertical faces of the free standing wall. Sides  118 ,  120  are preferably textured so as to form a double-sided textured wall. 
   A second embodiment of a stretcher block  14  is shown in  FIGS. 5C and 5D . This embodiment also includes a first load bearing face  110 , a second load bearing face  112 , a first end  114 , a second end  116 , a first side  118 , and a second side  120 , also shown in the embodiment of stretcher block  14  shown in  FIGS. 5A and 5B . 
   The embodiment shown in  FIGS. 5C and 5D  is different in that the structure of the inner cores  126 ,  128  shown in  FIGS. 5A and 5B  is divided to form two core segments  370  that are placed in the position of the secondary core, while the secondary core elements  134 , 138  combine to form a core portion  390  that is placed in the positions of the inner cores  126 ,  128 . 
   The interlock portion of any embodiment of the stretcher block  14  that is entirely contained on a single block may be referred to as a full interlock. The interlock portion on the end of a block which cooperates with another interlock portion at the end of another block may be referred to as a half interlock. 
   The details of construction shown with respect to the stretcher blocks in  FIGS. 5A ,  5 B,  5 C, and  5 D are merely exemplary embodiments of the stretcher block  14 , and should not be interpreted as limiting the scope of the claims appended to this application. Both embodiments, and others covered by the claims, can be used in the same fashion to form walls of blocks as described earlier. The stretcher block  14  is preferably symmetrical around a plane passing though the approximate center of the central core  122 , said plane being generally perpendicular to the load bearing face  110 . This means that preferably each inner core  126  looks like the other inner core  128  and each secondary core  134  looks like the other secondary core  138 . This enables simple wall construction since the blocks and their interlocks operate in a consistent fashion from end to end. 
   Stretcher Block or Double Unit Block  16  Having a Splitter Wedge at the Primary Core 
   As shown in  FIGS. 6A and 6B , stretcher block  16  is identical to stretcher block  14  with the exception of a pair of splitter wedges or recesses  170  at the central core  122 . Splitter wedges  170  are aligned with each other and are disposed in a plane that runs normal to load bearing faces  110 ,  112  and to sides  118 ,  120 . Each of the recesses  170  runs to and between the first and second load bearing faces  110 ,  112 . Each of the recesses  170  communicates with or opens to the central core  122 . 
   Splitter wedges  170  serve as an aid for field modification of stretcher block  16 . That is, by splitting block  16  along the plane defined by the pair of splitter wedges  170 , a left hand straight block or block portion  172  and a left hand straight block or block portion  174  is formed, with each of the newly formed blocks  172 ,  174  having secondary wall portions or seats for interlocks. 
   It should be noted that stretcher block  16  does not require field modification and may, if desired, be used in the same manner as stretcher block  14 . It should also be noted that the splitter wedge  170  can be used with central cores of configurations such as that in  FIGS. 5A ,  5 B,  5 C, and  5 D, as well as others covered by the claims. 
   Stretcher Block or Double Unit Block  18  Having a Splitter Wedge at One Interlock 
   As shown in  FIGS. 7A and 7B , stretcher block  18  is identical to stretcher block  14  with the exception of a splitter wedge  180  (or recesses  180 ) so as to form a discontinuous interlock  182  having a pair of interlocking segments  184 ,  186 . 
   Discontinuous interlock  182  is the same as discontinuous interlock  92  such that one interlocking segment  184  has a pair of ends or end faces  188  that are spaced from the ends or end faces  188  of the other interlocking segment  186  so as to therebetween form the splitter wedge or space or recess  180 . Space  180  runs to and between each of the load bearing faces  110 ,  112 . Space  180  opens to and communicates with the inner core  128 . 
   Splitter wedge  180  is a marker or aid for splitting stretcher block  18  into a one-quarter portion or left hand straight block  190  and a three-quarter portion or left hand straight block  192 . Spaces  180  are aligned with each other on a plane running normal to ends  110 ,  112  and sides  118  and  120 . Once split, the blocks  190  and  192  have end faces that run normal to ends  110 ,  112  and sides  118  and  120 . 
   It should be noted that stretcher block  18  does not require field modification and may, if desired, be used in the same manner as stretcher block  18 . It should also be noted that the splitter wedge  180  can be used with interlocks or cores located at positions such as those disclosed in  FIGS. 5A ,  5 B,  5 C, and  5 D, as well as others covered by the claims. 
   Mold Layout for Stretcher Blocks  14 ,  16 , and  18   
   As shown in  FIG. 8 , a preferred way of forming a texture or a rough masonry face on sides  116 ,  118  is by splitting one or more stretcher blocks  14 ,  16 , and  18  molded back to back, such as in a split-face machine. For example, mold box  194  includes a layout having a stretcher block  14 , a stretcher block  16  and a stretcher block  18  where sides of blocks  14  and  16  are formed by a split and where sides of blocks  14  and  18  are formed by a split. One side of block  16  is formed by a split with an excess masonry portion  196 . One side of block  18  is formed by a split with an excess masonry portion  198 . Other portions of blocks  14 ,  16  and  18  confront mold portions  200  and these other portions of blocks  14 ,  16  and  18  include at least the faces  110 ,  112 , ends  114 ,  116 , cylindrical wall  124  of the central core  122 , cylindrical walls  130 ,  132  of the relatively small inner cores  126  and  128 , interlocks  142  and  144 , chamfers  146 ,  148 ,  150 , and  152  and, in block  16 , recesses  170 , and further, in block  18 , recesses  180 . 
   Corner Block  20   
   As shown in  FIGS. 9A and 9B , corner block  20  generally includes a first load bearing face  202 , a second load bearing face  204 , a first end  206 , a second end  208 , a first side  210  and a second side  212 . Corner block  20  further includes a central or primary or inner core  214  defined by a cylindrical wall  216  and an inner core  218  defined by a cylindrical wall  220 . Corner block  20  further includes four corner faces or chamfers  222 ,  224 ,  226  and  228  that are disposed in planes normal to load bearing faces  202 ,  204 . 
   First load bearing face  202  is disposed opposite of second load bearing face  204 . Each of the load bearing faces  202 ,  204  is disposed in a plane that is parallel to the plane of the other load bearing face. Each of the load bearing faces  202 ,  204  is transverse to or lies at a crosswise direction relative to ends  206 ,  208 . Generally, each of the load bearing faces  202 ,  204  is trapezoidal. Specifically, each of the load bearing faces  202 ,  204  is bounded by a set of ten edges formed by chamfers  222 ,  224 ,  226 ,  228 , flat end  206 , end  208  having a secondary core portion, and sides  210 ,  212 . 
   Central core  214  is generally formed centrally in corner block  20  and extends to and between each of the load bearing faces  202  and  204 . An axis running centrally through central core  214  is equidistant from sides  210  and  212  and is further generally equidistant from ends  206  and  208 . 
   More particularly, an axis  229  running centrally through central core  214  and an axis  231  running centrally through inner core  218  are spaced from each other by a distance equal to the distance between axis  231  and axis  233 , which runs centrally through a secondary core portion  230  of end  208 , where secondary core portion  230  is defined by cylindrical wall  232 . 
   Such set distance between axis  229  and  231  and between axis  231  and  233  is also the set distance between 1) the axis of core  42  and the axis of each of the secondary core portions  46 ,  50  of angle blocks  10  and  12 ; 2) the axis of central core  122  and the axis of each of the inner cores  126  and  128  of stretcher blocks  14 ,  16  and  18 ; 3) the axis of inner core  126  and the axis of secondary core portion  138  of stretcher blocks  14 ,  16  and  18 ; 4) the axis of inner core  128  and the axis of secondary core portion  134  of stretcher blocks  14 ,  16  and  18 . 
   The diameter or size of the central core  214  in combination with the inner core  218  is sufficiently large so as to minimize the weight or mass of the corner block  20  and sufficiently small so as to provide sufficient mass and strength to corner block  20  such that a set of corner blocks, alone or in combination with other building blocks, can make up a free standing wall. 
   Corner block  20  does not include an interlock such as interlock  54 . However, cylindrical wall  220  of inner core  218  is the same diameter as the cylindrical walls of 1) 44 and 70 of angle blocks  10  and  12 ; and 2) cylindrical walls  130  and  132  of stretcher blocks  14 ,  16 , and  18  such that piping can be introduced through inner core  218  and cores of other blocks  10 ,  12 ,  14 ,  16 ,  18  and  20 . 
   It should further be noted that cylindrical wall  216  of central core  214  has the same radius as secondary core portion  230 , which radius is the same as 1) secondary core portions  46 ,  50  of angle blocks  10  and  12 ; and 2) central core  122  and secondary core portions  134  and  138  of stretcher blocks  14 ,  16  and  18 . 
   It should further be noted that central core  214 , like other central or primary cores, is a seat for a continuous interlock or one or more interlocking segments. 
   It should further be noted that secondary core portion  230 , like other secondary core portions, is a seat for a continuous interlock or one interlocking segment. 
   End  206  is disposed opposite of end  208 . End  206  is flat and runs in a plane normal to load bearing faces  202 ,  204  and sides  210 ,  212 . End  208  includes a first flat surface  234  and a second flat surface  236 , with each of the flat surfaces  234 ,  236  running normal to load bearing faces  202 ,  204 . Secondary core portion  230  is formed intermediate the flat surfaces  234 ,  236 . Flat surfaces  234 ,  236  lie in a plane that is oblique to each of sides  210 ,  212  and that is further oblique to the plane in which flat end  206  lies. Each of the flat surfaces  234 ,  236  is transverse to or lies at a crosswise direction to faces  202 ,  204  and sides  210 ,  212 . 
   By virtue of flat end  206  and oblique end  208  having an interlock seat or secondary core portion  230 , corner block  20  may form a portion of a corner or end of a free standing wall, with flat end  206  possibly being a terminal portion of the corner or end of the free standing wall. Such a free standing wall or row of building blocks may then run from oblique end  208 . 
   Sides  210 ,  212  of corner block  20  are disposed opposite of each other. Each of the sides  210 ,  212  is disposed generally in a plane that is generally parallel to the plane of the other side. Each of the sides  210 ,  212  is transverse to or lies at a crosswise direction relative to load bearing faces  202 ,  204  and ends  206 ,  208 . Sides  210 ,  212  and flat end  206  for exterior vertical faces of a free standing wall and are preferably textured so as to form a double-sided textured wall with corners or ends that are also textured. 
   Corner block  20  may be used “right-side up” or “upside-down”. In other words, either of the load bearing sides may be above the other. Likewise, blocks  10 ,  12 ,  14 ,  16 , and  18  may be used with either of the load bearing sides at a higher level. 
   Mold Layout for Corner Block 
   As shown in  FIG. 10 , a mold layout  240  for corner block  20  includes three corner blocks  20  having split lines or planes  242  for forming one or more of the textured sides  210 ,  212 . Two of the split planes  242  divide a corner block  20  from an excess masonry portion  244 . 
   Mold layout  240  further includes split lines or planes  246  for forming flat end  206  and that divide flat end  206  from an excess masonry portion  248 . 
   Remaining portions of corner block  20  confront mold portions  250  and these other portions includes at least the load bearing faces  202 ,  204 , the end  208  having the secondary core portion  230 , cylindrical wall  216  of central relatively large core  214 , cylindrical wall  220  of inner relatively small core  218 , and chamfers  222 ,  224 ,  226  and  228 . 
   Cap Block  22   
   As shown in  FIGS. 11A and 11B , a cap or cap block  22  is placed on an uppermost building block or uppermost row of building blocks  10 ,  12 ,  14 ,  16 ,  18  and/or  20 . Cap  22  includes two ends  260  and  262  that are mutually inclined relative to each other and that are coplanar with, or preferably extend slightly beyond ends  34  and  36  of angle blocks  10 ,  12  when cap  22  is placed on top of angle block  10  or  12 . Cap  22  further includes an upper flat face  264  that is opposite of a lower face  266  that includes two flat portions  268 ,  270  with a track  272  intermediate the flat portions  268 ,  270 . Flat portions  268 ,  270  are disposed in a plane that is generally parallel to a plane in which upper flat face  264  lies. Cap  22  further includes sides  274 ,  276  that are opposite of each other and that are disposed in planes that run parallel to each other and normal to flat portions  268 ,  270 . Track  272  is a receptor for an interlock, such as endless interlock  54 , discontinuous interlock  92 , endless interlocks  142 ,  144 , and discontinuous interlock  182 . When cap  22  is engaged on one of the building blocks, tapered track portions  278  confront tapered portions of such interlocks or interlock segments. 
   It should be noted that width of cap  22  (distance between sides  274  and  276 ) is greater than the width of any of the building blocks  10 ,  12 ,  14 ,  16 ,  18  and  20  (distance between the sides of such blocks) such that the cap  22  overhangs such building blocks. 
   It should be noted that cap  22  may or may not be placed directly over respective building blocks, but that the caps  22  may be placed in a staggered fashion relative to building blocks immediately below. In other words, in a row of building blocks, a line is formed where two ends of adjacent building blocks confront. A cap  22  may be placed directly over such a line to conceal the location where adjacent building blocks confront each other. 
     FIG. 18A  shows cap blocks  22  placed to form a cap of a straight wall portion such that side  260  of one cap block  22  confronts side  262  of the other cap block  22 . 
   Mold Layout for Cap Block 
   As shown in  FIG. 12 , cap or cap block  22  preferably includes no texture. Accordingly, in a mold layout  280 , where four caps or cap blocks  22  are formed, the cap blocks  22  are spaced from each other and no splits are formed anywhere. Mold portions  282  confront every surface of the cap or cap block  22 . 
   Post Cap Block  24   
   Post cap block  24  is shown in  FIGS. 13A ,  13 B and  13 C. Post cap block  24  includes an upper rectangular flat surface  284  and a set of three inclined surfaces  286 ,  288  and  290  leading downwardly and outwardly from the upper rectangular flat surface  284 . Surface  286  leads into a full length side  292  and surfaces  288  and  290  each lead into respective half length sides  294  and  296 . Surfaces  288  and  290  further lead into a back side  298 . Post cap block  24  further includes a flat bottom surface  300 . 
   When two post cap blocks  24  are placed back to back such that back sides  298  confront each other, a post cap is formed so as to be placed on top of a post, such as post  312  (shown in  FIG. 17B  in the process of being built). Such a post cap includes a square top flat surface formed by two surfaces  284  and four inclined surfaces extending downwardly and outwardly from the square top flat surface, where two of the four inclined surfaces are two surfaces  286  and where the other two of the four inclined surfaces are formed by one surface  288  confronting one surface  290  and by another surface  288  confronting another surface  290 . Post cap thereby has the appearance of a crown. The surface of such a crown is defined by such four inclined or trapezoidal areas converging upwardly toward the square flat surface that may be utilized for mounting a light fixture. The cap post building block  24  is preferably glued or otherwise fixed to the flat surfaces of upper portions of a post, where such post is most preferably formed by corner blocks  20  or by a combination of building blocks  10 ,  12 ,  14 ,  16 ,  18 , and  20 . Post cap block  24  preferably has a length and width sufficient so as to extend beyond one, two, three or four sides of a post. 
   Mold Layout for Post Cap Block 
   A mold  300  for the post cap block  24  is shown in  FIG. 14 . Post cap block  24  preferably includes no textured portions. Accordingly, all surfaces of the post cap block  24  are confronted by mold  300  or mold portions  302 . 
   A Straight Wall 
     FIG. 15A  shows a straight wall portion formed by a set of angle blocks  10 . In such a straight wall portion or lower row of angle blocks  10 , the first relatively short side  38  of one angle block  10  confronts the relatively long side  40  of an adjacent block, which in turn confronts the first relatively short side  38  of another angle block  10 . An upper row of angle blocks  10  may be interlocked with the straight wall portion shown by offsetting the upper row of angle blocks a distance of one-half of the length of an angle block  10  such that the endless interlocks  54  of the lower row of angle blocks  10  are seated in secondary cores formed by confronting secondary core portions  46 ,  50  of confronting upper angle blocks  10 . 
     FIG. 15B  shows a straight wall portion formed by stretcher blocks  14 . Another straight wall portion of stretcher blocks  14  may be placed on the first mentioned or lower straight wall portion, with the second mentioned or upper straight wall portion being offset the distance of one-quarter of a stretcher block from the lower straight wall portion such that the interlocks  142 ,  144  of the stretcher blocks  14  of the lower straight wall portion are seated in central core  122  and secondary core portions  134  and  138  of the upper building blocks. Such an offset and interlock continues with each row of stretcher blocks  14 . 
   A Curved Wall 
     FIG. 16A  shows a curved wall portion or upper row formed by angle blocks  10  where the relatively short sides  38  of the angle blocks  10  confront each other and where the relatively long sides  40  confront each other. An upper row of angle blocks  10  is interlocked with the lower row by offsetting the upper row by a distance of one-half of an angle block  10  such that the endless interlocks  54  of the lower row are seated in the secondary cores formed by secondary core portions  46 ,  50  of the upper row. 
     FIG. 16B  shows a curved wall portion formed by angle block  10 , stretcher block  14 , block  102  (a field modified version of block  12 ) and a corner block  20  placed “upside-down”. It should be noted that curves of a great variety of different slopes may be formed by confronting different ends of different blocks and their field modified versions. 
   A Corner 
   Corner wall portions, such as corner wall portion  310  is shown in  FIG. 17A , may be formed utilizing corner blocks  20  (having texture on two sides and an end) with field modified block or three quarter block  192  where each of the corner block  20  and field modified block  192  are staggered as the corner  310  is formed. Extending from the corner  310  (or corner block/field modified block combination), may be one or more of the angle blocks  10 , angle blocks  12 , stretcher blocks  14 , stretcher blocks  16 , and stretcher blocks  18  (all of which have texture on two sides). The corner blocks  20  form the extreme corner of the corner wall portions and the remaining blocks tie into the corner blocks  20  with one or more interlocks, such as interlocks  54 ,  92 ,  142 ,  144 , and  182  (including interlock segments  184 ,  186 ). Posts may be inserted through aligned cores of the blocks and further into the ground to provide resistance to over-turning of the corner wall portion. 
   A Post 
     FIG. 17B  shows a masonry post  312  formed by the corner blocks  20 . Each of the sides of the post  312  is formed by staggered layers of a side  212  of one corner block  20  and an end  206  of another corner block  20 . Glue and/or piping may be used to interlock the corner blocks  20  to each other. A piece of pipe may extend through inner cores  231  that are aligned with each other and/or through the central cores  214  and second core portions  230  that are aligned with each other. 
   Each of the masonry posts  312  includes a pair of post caps blocks  24  placed end to end so as to form a post cap. The post cap preferably is sufficiently large so as to somewhat overhang the sides of the post. 
   Piping 
   As shown in  FIG. 18A , piping  320 , where used, such as shown in  FIG. 18A , may be a piece of steel tubular piping and may have an outside diameter of preferably about one and three-eighths of an inch. The outside diameter of the piping preferably is slightly less than or equal to the inside diameter of the interlocks of the present invention, such as endless interlock  54  whereupon piping confronts every other block of the present invention. In other words, piping extends through and confronts an interlock of one block, then immediately extends through a primary core or secondary core portion of an immediately adjoining block, then immediately extends though and confronts the interlock of the next block in the next level. 
   Such piping is easily cut by a pipe cutter in the field. Piping may be preferred where walls or wall portions are greater than about three or about four feet in height. 
   Random Looks 
     FIG. 18B  shows how a wall portion of the present invention may have a random look. Such a wall can have one of more of angle blocks  10 , one or more of angle blocks  12  and/or its field modified versions, one or more of stretcher blocks  14 , one or more of stretcher blocks  16  and/or its field modified versions, one or more of stretcher blocks  18  and/or its field modified versions, one or more of corner blocks  20 , and one or more of cap blocks  22 . 
   Further, one or more of the blocks in the random look may have scores  330  formed in the surface to provide the appearance of a half-block when in actuality the block is a full block, such as stretcher block  14 . As to forming such a score  330 , the following U.S. patents are incorporated by reference in their entireties: the Bott U.S. Pat. No. 6,082,067 issued Jul. 4, 2000 and entitled Dry Stackable Block Structures and the Bott U.S. Pat. No. 6,322,742 issued Nov. 27, 2001 and entitled Method of Producing Stackable Concrete Blocks. 
   A Serpentine Wall 
   A serpentine or undulating wall can be formed by 1) curved wall combinations, 2) straight wall combinations and/or 3) curved and straight wall combinations. For example,  FIG. 19A  shows a serpentine wall portion  340  formed by curved wall portions shown in  FIG. 16A . The serpentine wall portion  310  uses ten angle blocks  10  for one full “wavelength,” but as few as four angle blocks  10  can be used for one full “wavelength” for a serpentine wall portion  340 . A second “wavelength” of ten angle blocks  10  may be placed in interlocking fashion on top of the undulating row  340  shown in  FIG. 19A , with the second “wavelength” of ten angle blocks being offset from the undulating row  340  by a distance of one-half the length of one angle block  10  such that the secondary core portions of the second “wavelength” are seated in the interlocks  54  of the first “wavelength.” 
   Another type of serpentine wall is shown in  FIG. 19B  where a zig-zag type of serpentine wall portion  350  includes a number of corners, such as corner  310  as shown in  FIG. 17A . Here a second “wavelength” may be placed on top of the wall portion  350  with the corner blocks  20  being staggered as shown in  FIG. 17A  for each of the corners  310  such that the field modified block  192  interlocks the corners  310  to each other. 
   Blocks of the present invention, other than that shown in  FIGS. 19A and 19B , may be used to form serpentine walls or zig-zag like walls. 
   With all other factors being equal, a serpentine wall has a relatively great amount of stability when compared to a straight wall. For example, whereas a straight wall may be considered to have stability merely along the longitudinal length of the wall, a serpentine wall has stability both in the longitudinal and lateral directions. 
   Stability of the Wall 
   Stability of a wall formed by one or more blocks of the present invention is provided by one or more of the following features: 1) the interlocking and seating features of the blocks; 2) the mass of the blocks used in the wall; 3) the flatness of the upper and lower faces of the blocks; 4) the shape of the wall, especially where serpentine or zig-zag or “step function” like walls are built; and 5) piping, as described above, running downwardly in the cores and driven into the ground. 
   Stability of the Wall—Interlocking of the Blocks 
   As to the interlocking and seating features, the interlocks ( 54 ,  92 ,  94 ,  96 ,  142 ,  144 ,  182 ,  184 ,  186 ) of lower blocks can be seated in the relatively large cores ( 122 ,  214 ) and in the secondary cores formed by the secondary core portions ( 46 ,  50 ,  134 ,  138 ,  230 ) of the upper blocks. It should be noted that the relatively small cores ( 42 ,  126 ,  128 ,  218 ) cannot provide seats for the interlocks since these relatively small cores are of a lesser size (lesser radius or diameter) than the outside diameter or radius of the interlocks. Cores  42 ,  126 ,  128  and  218  are interlock-excluding cores. Cores  122 ,  214  are interlock-receiving or interlock-seating cores. The secondary cores are interlock-receiving or interlock-seating cores, such as via their size or such as via their shape. The interlocks cannot fit into the such relatively small cores  42 ,  126 ,  128  and  218  and thereby provide a warning to one constructing a wall that he or she has not found a proper interlocking fit. In other words, the only proper fit between adjoining blocks of different height is a self-aligning interlocking fit. In still other words, if, upon laying one of the blocks upon a lower row of blocks, the lower face of the just laid down block is flat against the upper face of the lower row, then one can be assured that he or she has an interlocking fit. In yet other words, adjoining blocks of different height do not interlock if one attempts to seat an interlock core upon an interlock. 
   Stability of the Wall—Mass or Density of the Block 
   As to the mass or weight of the blocks, the density of a block is preferably between about 120 pounds per cubic foot and about 140 pounds per cubic foot, more preferably between about 125 and about 140 pounds per cubic foot, and most preferably between about 130 pounds per cubic foot and about 140 pounds per cubic foot. The weight of a block is preferably sufficiently small to permit the block to be managed by a homeowner (e.g., to be lifted into place about three or four feet from the ground by an adult woman or adult man of average strength). The weight of the block is preferably as great as possible to lend as much stability to the wall as possible. 
   Stability of the Wall—Flatness of the Load Bearing Faces 
   Without taking into account the interlocks or interlocking segments, the upper faces ( 30 ,  110 ,  202 ) and lower faces ( 32 ,  112 ,  204 ) of the blocks ( 10 ,  12 ,  14 ,  16 ,  18 ,  20 ) are preferably as flat as possible. In other words, the upper and lower faces are preferably free of recesses or extensions except for the interlocks, cores and secondary core portions. In still other words, not taking into account the interlocks, cores, or secondary core portions, the upper and lower faces are preferably 90% free of such nonflat features, more preferably 95% free of such nonflat features, and yet more preferably 99% free of such nonflat features, and most preferably 99.9% or more free of such nonflat features. In considering flatness, the standard rough surface of a cement block and the usual nicks in a surface of such cement block are not taken into account. Given the standard rough surface and the usual nicks, the upper and lower faces are substantially flat with no recesses, no grooves, no scores, no extensions, no nubs, no ribs, or any other feature deviating from a flat surface. Such flatness provides a downward load or force that is equalized or spread out over the entire wall, thereby providing for relatively great stability. Flatness further means that “all points of the upper surface shall be contained between two parallel planes, the base plane and the roof plane, separated by a distance no greater than that specified and that all points of the lower surface shall be contained between two parallel planes, the base plane and the roof plane, separated by a distance no greater than that specified.” Such a specified distance is preferably less than about one-quarter of an inch, more preferably less than about one-eighth of an inch, yet more preferably less than about one-sixteenth of an inch, and most preferably less than about one-thirty seconds of an inch. Flatness further means that the upper surface lies in a plane that is parallel to a plane in which the lower surface lies. 
   Such blocks where flatness is maximized also provide for maximizing friction in the lateral and longitudinal directions. This minimizes the chance that during construction of a wall, a block is knocked or slid off a wall, whereupon the block break upon hitting the ground. 
   Composition of Blocks 
   Each of the blocks  10 ,  12 ,  14 ,  16 ,  18 ,  20 ,  22 ,  24  may be formed by almost any variety of a concrete mixture or fill. The mixture or fill may depend upon a number of factors, including the desired strength of the block, the desired water absorption, the desired density, the desired shrinkage and other physical characteristics. A cementatious mixture for such blocks may include one or more of cement, fly ash, water, sand, gravel, rock, plasticizers, water proofing agents, crosslinking agents, dyes, colorants, and pigments. 
   Exposed Surfaces of the Blocks 
   The exposed surfaces of the blocks of the present invention, such as where the exposed surfaces are the sides  38 ,  40  of angle blocks  10 ,  12 , or the sides  118 ,  120  of stretcher blocks  14 ,  16 ,  18 , or the sides  210 ,  212  and end  206  of corner block  20 , are preferably finished. A finished surface may be textured or nontextured. A finished surface may be antiqued or nonantiqued. A finished surface that is textured is preferred. A finished surface that is textured by using the mold layouts of the present invention, such as the mold layouts of  FIG. 4 ,  8 , or  10 , is more preferred. 
   Construction of walls according to the present invention provides the opportunity to have both vertical surfaces of the wall finished based on the form and fit of the individual units or blocks. This feature develops the basis for a structure that is functional and that is architecturally appealing. 
   While exemplary embodiments of this invention and methods of practicing the same have been illustrated and described, it should be understood that various changes, adaptations, and modifications might be made therein without departing from the spirit of the invention and the scope of the appended claims.

Summary:
The present building block has at least one load bearing surface, the load bearing surface of the block having mating interlocking portions comprising cores and protruding interlocks receivable in the cores. The blocks are configured so that each end of a block comprises a half interlock and adjacent ends of a pair of blocks in a course together define an interlock portion that interlocks with a mating full interlock portion carried by a block in an adjacent course of blocks. The basic building block has ends that are oblique such that rows having a preset radius can be formed or such that a linear row can be formed by placing one block front-to-back and an adjacent building block back-to-front. Disclosed are angle blocks with and without splitter wedges, stretcher blocks with and without splitter wedges, blocks for forming corners and posts, cap blocks, and blocks for capping posts.