Abstract:
A retaining wall system is comprised of a plurality of courses of side-by-side parallelogram front face patterns, each parallelogram front face pattern formed by first and second rows of a plurality of quadrilateral face patterns. The first and second rows of the plurality of quadrilateral face patterns have the same width and collectively define a height of the parallelogram front face pattern, with each of the parallelogram front face patterns having the same height. The quadrilateral face patterns in the first row have a width different than that of the quadrilateral face patterns in the second row. Each parallelogram front face pattern in a first course overlies two parallelogram front face patterns in an immediately adjacent course. The combination of off-sets of the quadrilateral face patterns in each parallelogram front face pattern and overlapping of parallelogram face patterns in adjacent courses creates a retaining wall having a non-uniform appearance of a natural stone wall.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
   This application is a continuation of application Ser. No. 10/230,025, filed Aug. 28, 2002 now U.S. pat. Ser. No. 6,960,048, which is a continuation of application Ser. No. 09/479,521, filed Jan. 7, 2000, now U.S. Pat. No. 6,488,448, which is a continuation-in-part of application Ser. No. 29/112,442, filed Oct. 15, 1999, now abandoned, and a continuation-in-part of application Ser. No. 29/112,434, filed Oct. 15, 1999, now U.S. Pat. No. D435,302. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to segmented retaining wall systems for soil retention or other environmental or aesthetic uses. In particular, the invention relates to retaining wall systems using masonry blocks to create modules resulting in a random appearance of the face of a retaining wall. 
   Segmented retaining wall systems are commonly used for residential, commercial and governmental projects. Transportation departments and the U.S. Army Corps of engineers routinely use retaining wall systems to retain soil and other structures. These systems can create straight or curved walls and can even be used along shore lines where embankment control is desired. 
   Segmented retaining wall systems can be comprised of poured slabs, bricks, natural stone, masonry blocks or other components. Individual units can be held together by mortar, other adhesives, gravity, pins, or other fasteners. 
   Uniform bricks or masonry blocks can provide a stable, durable and attractive retaining wall. However, these walls tend to have a very homogenous and uniform appearance that may not be suitable for every project. Sometimes a more unique randomized retaining wall or landscape is desired. 
   Natural stone can be used to provide a unique random appearance to a landscape. However, without the use of mortar or some other adhesive/sealant, natural stone retaining walls have poor soil retention properties. Additionally, Natural Stone retaining walls are expensive and cumbersome to construct. It is therefore desired to create a retaining wall system that maintains the unique random quality of a natural stone wall surface, with the structural and soil retention properties, as well as the economic efficiencies, of man-made masonry block walls. 
   Working with masonry blocks of different size affects the securing methods typically used during construction. A mortarless wall that uses pins to secure masonry blocks would require numerous pins of different sizes corresponding to the size of the particular masonry block. Installers have the burden of keeping track of the appropriate pins and using them accordingly. It is desirable to have a universal securing pin that could be used with different sized masonry blocks. 
   Depending on the requirements of the landscape, the composition of the soil, the height of a wall, or the desired aesthetic appearance of a wall, a segmented retaining wall may need to be canted or vertical. It is desirable to have masonry blocks for a mortarless segmented retaining wall that can be used to build either a canted wall or a vertical wall. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is a retaining wall system having a front wall face defined by a plurality of parallelogram face patterns. Each parallelogram face pattern of the plurality of parallelogram face patterns has a generally similar height and width. The plurality of parallelogram face patterns are arranged side-by-side and in successive courses. Each parallelogram face pattern comprises a first row of a plurality of quadrilateral face patterns, the first row having a width, and a second row of a plurality of quadrilateral face patterns, the second row having a width generally equal to the width of the first row. Each of the quadrilateral face patterns of the first row have a width different than that of each of the quadrilateral face patterns of the second row. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be further explained with reference to the drawing figures referenced below, wherein like structure is referred to by like numerals throughout the several views. 
       FIG. 1  is a partial perspective view of an embodiment of the modular segmented retaining wall of the present invention. 
       FIG. 2  is a perspective view of a first module of the present invention shown in the context of a modular segmented retaining wall. 
       FIG. 3  is a perspective view of a second module of the present invention shown in the context of a modular segmented retaining wall. 
       FIG. 4  is a perspective view of a third module of the present invention shown in the context of a modular segmented retaining wall. 
       FIG. 5  is a perspective view of a fourth module of the present invention shown in the context of a modular segmented retaining wall. 
       FIG. 6  is a perspective view of a fifth module of the present invention shown in the context of a modular segmented retaining wall. 
       FIG. 7  is a perspective view of a sixth module of the present invention shown in the context of a modular segmented retaining wall. 
       FIG. 8  is a perspective view of a first masonry block of the present invention. 
       FIG. 8A  is a top plan view of the first masonry block of  FIG. 8 . 
       FIG. 8B  is a side elevational view of the first masonry block of  FIG. 8 . 
       FIG. 9  is a perspective view of a second masonry block of the present invention. 
       FIG. 9A  is a top plan view of the second masonry block of  FIG. 9 . 
       FIG. 9B  is a side elevational view of the second masonry block of  FIG. 9 . 
       FIG. 10  is a perspective view of a third masonry block of the present invention. 
       FIG. 10A  is a top plan view of the third masonry block of  FIG. 10 . 
       FIG. 10B  is a side elevational view of the third masonry block of  FIG. 10 . 
       FIG. 11  A is a perspective view of an embodiment of a retaining wall pin of the present invention. 
       FIG. 11B  is a front elevational view of the retaining wall pin of  FIG. 11A . 
       FIG. 11C  is a bottom plan view of the retaining wall pin of  FIG. 11A . 
       FIG. 12  is a perspective view of a portion of the modular segmented retaining wall of  FIG. 1  with parts of the wall removed to illustrate its construction. 
       FIG. 13  is a side elevational view of an embodiment of a canted modular segmented retaining wall of the present invention. 
       FIG. 14  is a side elevational view of an embodiment of a nearly vertical modular segmented retaining wall of the present invention. 
   

   While the above-identified drawings set forth preferred embodiments of the present invention, other embodiments of the present invention are also contemplated, as noted in the discussion. This disclosure presents illustrative embodiments of the present invention by the way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this invention. 
   DETAILED DESCRIPTION 
     FIG. 1  illustrates an embodiment of the modular retaining wall of the present invention. Retaining wall  10  includes modular wall body  12  and cap course  14 . Wall body  12  and cap course  14  are formed by stacking individual masonry blocks. Retaining wall  10  can be a straight wall or can be curved with either a convex or concave curvature to follow the specific requirements of a landscape. Retaining wall  10  can be canted or nearly vertical. The modular wall body  12  provides a unique appearance to wall  10  without requiring each masonry block contained therein to be uniquely shaped or sized. 
   Wall body  12  is formed with masonry blocks  16 ,  18 , and  20  (masonry blocks  16 ,  18 , and  20  will be discussed in further detail with respect to  FIGS. 8–10 ). Masonry blocks  16 ,  18 , and  20  are of different dimensions and are combined to form modules  22 . Modules  22  are formed by assembling various combinations of masonry blocks  16 ,  18 , and  20 , while maintaining constant overall dimensions of modules  22  and front surface area of modules  22 . Modules  22  are interchangeably arranged to form modular retaining wall  10 . Modules  22  are like separate larger blocks with ascending courses of modules  22  having variable canting and variable bond (i.e., variable lateral spacing of blocks from one course to the next). Arranging modules  22  interchangeably creates a segmented retaining wall bearing the non-uniform appearance of a natural stone wall. 
   Cap course  14  is installed on top of modules  22  forming the top course of retaining wall  10 . Cap course  14  preferably includes cap stones  30  and  32 . Cap stones  30  and  32  are trapezoidal in shape. Cap stone  30  includes front textured face  34 , rear face  36 , and sides  38 . Sides  38  of cap stone  30  connect front textured face  34  and rear face  36 . Front textured face  34  is wider than rear face  36 , and sides  38  angle inward as sides  38  recede toward rear face  36 . Cap stone  32  includes front textured face  40 , rear face  42 , and sides  44 . As with cap stone  30 , sides  44  connect faces  40 , and  42 . However, sides  44  angle outward as sides  44  recede toward rear face  42 . 
   For retaining wall  10  without curves, cap stones  30  and  32  alternate so that respective front textured faces  34  and  40  form a flush continuous rim. A retaining wall  10  having a convex (outside) curve will include cap course  14  that includes only cap stones  30  so that front surfaces  34  form a curved continuous rim. A retaining wall  10  with a concave (inside) curve will include a cap course  14  having only cap stones  32 , where front surfaces  40  form a curved continuous rim. 
   Front textured surfaces  34  and  40  have the same dimensions and surface area. Preferably, textured front surfaces  34  and  40  of cap stones  30  and  32  are 14 inches wide and 35 inches high. Preferably, cap stones  30  and  32  are 12 inches deep. The width of rear face  36  of cap stone  30  is 16 inches, and the width of rear face  42  of cap stone  32  is 12 inches. 
   Modules 
   Preferably, blocks  16 ,  18 , and  20  are arranged to create six different patterned modules  22 A,  22 B,  22 C,  22 D,  22 E, and  22 F. (Referred to collectively to as modules  22 ).  FIGS. 2–7  illustrate each of the six modules  22 . Each module  22  includes top course  24  and bottom course  26 . Top course  24  has a first height h 1  and bottom course  26  has second height h 2 . The height of each module  22  is the sum of height h 1  and height h 2 . Each module  22  has a width w that is equal to the combined width of its masonry blocks. Modules  22  are arranged interchangeably during construction of retaining wall  10  because the modules  22  have roughly the same dimensions including an identical exposed front surface area ([height h 1 +height h 2 ]×width w). 
   Module  22 A includes two masonry blocks  18  adjacent to each other in top course  24 , and includes block  16  positioned to the right of block  20  in bottom course  26 . (See  FIG. 2 ). Module  22 B includes block  16  positioned to the left of block  20  in top course  24 , and includes two blocks  18  in the bottom course  26 . (See  FIG. 3 ). Module  22 C includes two blocks  18  in top course  24 , and includes block  16  to the left of block  20  in bottom course  26 . (See  FIG. 4 ). Module  22 D includes block  16  to the right of block  20  in top course  24 , and two blocks  18  in bottom course  26 . (See  FIG. 5 ). Module  22 E includes three blocks  20  in top course  24 , and two blocks  18  in bottom course  26 . (See  FIG. 6 ). Module  22 F includes two blocks  18  in top course  24 , and three blocks  20  in bottom course  26 . (See  FIG. 7 ). Construction of retaining wall  10  is discussed below with respect to  FIG. 12 . 
   The Masonry Blocks 
   Masonry blocks  16 ,  18 , and  20  are mortarless retaining wall blocks that are held together by gravity and pins. The primary difference between masonry blocks  16 ,  18 , and  20  is the size and shape of the blocks. However, all masonry blocks  16 ,  18 , and  20  can be coupled to one-another. Masonry blocks  16 ,  18 , and  20  all receive and accommodate retaining pins, which are used to hold the blocks together. Furthermore, masonry blocks  16 ,  18 , and  20  can be used to build a vertical wall or an angled wall. Each of masonry blocks  16 ,  18 , and  20  will be discussed separately below. 
     FIGS. 8 ,  8 A, and  8 B, show, in detail, masonry block  16 . Masonry block  16  includes top surface  48 , bottom surface  49 , front face  50 , sidewalls  52 , 54 , and rear face  56 . As shown, the block faces have a number of slots and holes therein, including horizontal splitting groove  58 , rear vertical splitting groove  60 , set-back pin holes  62 A,  62 B,  62 C, and  62 D (collectively referred to as set-back pin holes  62 ), set-back receiving slots  64 A and  64 B (collectively referred to as set-back receiving slots  64 ), vertical pin holes  66 A and  66 B (collectively referred to as vertical pin holes  66 ), and vertical receiving slots  68 A and  68 B (collectively referred to as vertical receiving slots  68 ). 
   Block  16  has a trapezoidal shape where front face  50  and rear face  56  are parallel. Sidewalls  52  and  54  angle inward as sidewalls  52  and  54  recede toward rear face  56 . Thus front face  50  is wider than rear face  56 . 
   Sidewalls  52  and  54  and rear face  56  are smooth while front face  50  is textured. The textured appearance is accomplished by splitting a hardened masonry block. Masonry blocks  16  are initially manufactured “piggyback”, where two blocks  16  are manufactured facing each other as one slab (not shown). A central splitting groove (not shown) along the single slab divides what will become two blocks  16 . After hardening, the slab is split into two blocks  16  along the central splitting groove creating two textured surfaces  50 . A masonry block can be split by a splitting device or by hand using a masonry chisel and large hammer. After scoring a desired path of the split, the unit is fractured along the scored path to create an attractive textured surface. 
   When it is necessary to have a textured front and back surface, such as used in a free-standing wall having exposed front and rear surfaces, horizontal splitting groove  58  is used. Horizontal splitting groove  58  extends across top surface  48  from sidewall  52  to sidewall  54 . Masonry block  16  is split along horizontal splitting groove  58 , removing a small rear portion and creating a textured rear surface. For installing corners of a wall, where both a front and a side surface need to be textured, vertical splitting groove  60  is used. Rear vertical splitting groove  60  extends across rear face  56  from top surface  48  to bottom surface  49 . Splitting masonry block  16  along rear vertical splitting groove  50  creates a textured sidewall extending between front face  50  and rear face  56 . Preferably, grooves  58  and  60  are triangular impressions into top surface  48  and rear face  56 , respectively. The triangular impressions are a quarter inch deep and are half inch wide. 
   For constructing canted walls, set-back pinholes and set-back receiving slots are used. Set-back pin holes  62  are cylindrical openings that extend through masonry block  16  from top surface  48  to bottom surface  49 . Set-back pin holes  62  allow for insertion of retaining pins to help secure succeeding courses of retaining wall  10  (retaining pins will be described below with respect to  FIGS. 11–12 ). Masonry block  16  has four set-back pin holes  62  and two set-back receiving slots  64 . Set-back pin holes  62 A and  62 B are positioned in front of set-back receiving slot  64 A, while set-back pin holes  62 C and  62 D are positioned in front of set-back receiving slot  64 B. The front-to-front spacing between set-back pin holes  62  and set-back receiving slots  64  determines the amount of set-back between two courses of blocks. During installation of canted retaining walls, block  16  is positioned over an underlying block so that certain of set-back pin holes  62  line up directly over set-back receiving slots of the underlying block. 
   Set-back receiving slots  64 A and  64 B are hollow channels that extend from sidewalls  52  and  54 , respectively, into the body of masonry block  16 . Set-back receiving slots  64  of block  16  receive retaining pins from overlying masonry blocks. Set-back receiving slots  64  are elongated to allow flexibility in the amount of variable bond and to allow masonry block  16  to receive retaining pins from masonry blocks  18  and  20 . As seen in  FIGS. 8 and 8B , set-back receiving slots  64  taper as they descend away from top surface  48 . Each set-back receiving slot  64  further includes inner edge  70  and lower edge  72 , both of which are rounded. Inner edge  70  runs vertically from top surface  48  into the block body, while lower edge  72  runs horizontally from sidewall  52  or  54  to the bottom of inner edge  70 . 
   Preferably, set-back pin holes  62  have a diameter of ⅝ inch. Preferably, set-back receiving slots  64  have a width at top surface  48 , that is equal to the diameter of set-back pin holes  62 . Set-back pin hole  62 B is aligned with inner edge  70  of set-back receiving slot  64 A, and set-back pin hole  62 C is aligned with inner edge  70  of set-back receiving slot  64 B, wherein the center of each pin hole  62 B and  62 C is spaced laterally 1¾ inches from the center line of masonry block  16 . The lateral distance separating set-back pinholes  62 A and  62 B is the same as the lateral distance separating set-back pinholes  62 C and  62 D. That distance is greater than the distance separating set-back receiving slots  64 A and  64 B. Preferably, set-back pin holes  62 A and  62 C are spaced laterally 4⅛ inches away from set-back pin holes  62 B and  62 D, respectively. Set-back pin holes  62  are positioned ¾ inch forward of set-back receiving slots  64 . 
   For near-vertical wall construction, vertical pin holes  66  and vertical receiving slots  68  are used. Vertical pin holes  66  are positioned between set-back receiving slots  64  and vertical receiving slots  68 . More specifically, vertical pin holes  66  are only slightly spaced forward of vertical receiving slots  68  and partially overlap them. Vertical pin holes  66  are only partially cylindrical because near top surface  48  vertical pin holes  66  extend through vertical receiving slots  68  and appear as semi-circular grooves running vertically along vertical receiving slot  68 . The portion of vertical pinholes  66  that lies below vertical receiving slots  68  is cylindrical in shape and identical to set-back pin holes  62 . 
   Preferably, set-back receiving slots  64  and vertical receiving slots  68  are 1⅞ inches deep. Vertical pin holes  66  have a ⅝ inch diameter and are spaced 4 7/16 inches to either side of the center line of masonry block  16 . Vertical pin holes  66  partially project through vertical receiving slots  68  so that the center of vertical pin holes  66  is positioned ¼ inch forward of the center line of vertical receiving slots  68 . 
   During installation of near-vertical retaining walls, block  16  is positioned over an underlying block so that certain of vertical pin holes  66  line up directly over vertical receiving slots of the underlying block. Some amount of set-back is provided, in the near-vertical alignment, by the offset of vertical pin holes  66  from vertical receiving slots  68 . The initial set-back is provided to accommodate the natural forces and stress applied on the wall by the backfill during construction. The forces applied by the backfill push the resulting wall forward into an essentially vertical alignment. Attempting to construct a vertical wall without any initial set-back would result in a retaining wall that leans forward once completed due to the forces applied by the backfill. 
   Masonry block  16  is preferably made from high-strength, low-absorption concrete on standard block molding machines. Preferably, masonry block  16  is 6 inches high and 12 inches deep. Front face  50  of block  16  is 16 inches wide and rear face  56  is 14 inches wide. Masonry block  16  is resistant to damage during and after construction in all climates and provides unsurpassed durability. 
     FIGS. 9 ,  9 A, and  9 B, show, in detail, masonry block  18 . In the modular retaining wall of the present invention, masonry block  18  is used in the opposite course of masonry blocks  16  and  20  in all modules  22 . But-for its shape and dimensions, masonry block  18  is identical to masonry block  16 . Masonry block  18  includes front face  80 , rear face  82 , sidewalls  83 A and  83 B, top surface  84 , and bottom surface  86 . As shown, the block faces have a number of slots and holes therein, including horizontal splitting groove  88 , rear vertical splitting groove  90 , set-back pin holes  92 A,  92 B,  92 C, and  92 D (collectively referred to as set-back pin holes  92 ), set-back receiving slots  94 A and  94 B (collectively referred to as set-back receiving slots  94 ), vertical pin holes  96 A and  96 B (collectively referred to as vertical pin holes  96 ), and vertical receiving slots  98 A and  98 B (collectively referred to as vertical receiving slots  98 ). 
   As described above with respect to masonry block  16 , masonry block  18  is also trapezoidal with front face  80  being wider than rear face  82 , and masonry block  18  includes four set-back pin holes  92  (see set-back pin holes  62  of  FIG. 8 ), two set-back receiving slots  94  (see set-back receiving slots  64  of  FIG. 8 ), two vertical pin holes  96  (see vertical pin holes  66  of  FIG. 8 ), two vertical receiving slots  98  (see vertical receiving slots  68  of  FIG. 8 ), horizontal splitting groove  88  (see horizontal splitting groove  58  of  FIG. 8 ), and rear vertical splitting groove  90  (see rear vertical splitting groove  60  of  FIG. 8 ). Like masonry block  16 , masonry block  18  is used to construct near-vertical or canted segmented retaining walls, and can be coupled to any of masonry blocks  16 ,  18 , and  20 . Masonry blocks  18  are manufactured in the same manner as blocks  16 . 
   Masonry block  18  has a smaller width and height than masonry block  16 . Preferably, front face  80  of masonry block  18  is 12 inches wide (compared to the 16 inch width of front face  50  of block  16 ) and rear face  82  is 8 inches wide (compared to the 14 inch width of rear face  56  of block  16 ). Block  18  is preferably 4 inches high and 12 inches deep. Masonry block  18  is preferably made from high-strength, low-absorption concrete on standard block molding machines. 
   Preferably, set-back pin holes  92  and vertical pin holes  96  have diameters of ⅝ inch. As with masonry block  16 , the two inner most set-back pin holes  92 B and  92 C are aligned with an inner edge of their respective receiving slot  94 A and  94 B, wherein the center of each pinhole  92 B and  92 C is spaced laterally 1 19/16 inches from the center line of masonry block  18 . Also as with masonry block  16 , the lateral distance separating set-back pin holes  92 A and  92 B is the same as the lateral distance separating set-back pinholes  92 C and  92 D. That lateral distance is 2⅜ inches. Set-back pin holes  92  are positioned ¾ inch forward of set-back receiving slots  94 . 
   Preferably, set-back receiving slots  94  and vertical receiving slots  98  are 1¼ inches deep. Vertical pin holes  96  are spaced 2 11/16 inches to either side of the center line of masonry block  18 . Vertical pin holes  96  partially project through vertical receiving slots  98  so that the center of vertical pin holes  96  is positioned ¼ inch forward of the center line of vertical receiving slots  98 . 
     FIGS. 10 ,  10 A, and  10 B show, in detail, masonry block  20 . Masonry block  20  is the smallest of masonry blocks  16 ,  18  and  20  of the present invention, and block  20  resembles (in dimension) a masonry block  16  that has been split in half along rear vertical splitting groove  60 . Masonry block  20  includes front face  100 , rear face  102 , top surface  104 , bottom surface  106 , and sidewalls  108  and  110 . As shown, the block faces have a number of slots and holes therein, including set-back pin holes  112 A and  112 B (collectively referred to as set-back pin holes  112 ), set-back receiving slot  114 , vertical pin holes  116 A and  116 B (collectively referred to as vertical pin holes  116 ), vertical receiving slot  118 , and horizontal splitting groove  120 . 
   Masonry block  20  has the same height as masonry block  16  and is used in the same course of modules  22 A,  22 B,  22 C, and  22 D as masonry block  16 . The width of masonry block  20  combined with the width of masonry block  16  equals twice the width of masonry block  18 . The width of three masonry blocks  20  also equals twice the width of masonry block  18 . 
   As with masonry blocks  16  and  18 , masonry block  20  is also trapezoidal in shape and has a textured front surface (front face  100 ). To create a textured rear surface, masonry block  20  is split along horizontal splitting groove  120 . Unlike masonry blocks  16  and  18 , masonry block  20  only has two set-back pin holes  102  as opposed to four set-back pinholes in masonry blocks  16  and  18 . To maintain a consistent canting of segmented retaining wall  10 , the amount of the set-back is kept constant among all three masonry blocks  16 ,  18  and  20 . Thus, set-back pin holes  112  of masonry block  20  are ¾ inch forward of set-back receiving slot  114 . Preferably, set-back pin holes  112  have the same dimensions as set-back pin holes  62  of masonry block  16  ( FIG. 8 ) and set-back pin holes  92  of masonry block  18  ( FIG. 9 ). Preferably, set-back pin hole  112 A is positioned 3 13/16 inches from set-back pin hole  112 B. 
   Set-back receiving slot  114  of masonry block  20  is an elongated channel that extends across top surface  104  from sidewall  108  to sidewall  110  and partially down into the body of masonry block  20 . During installation, set-back receiving slot  114  rests below a set-back pin hole of the block above and receives a retaining pin that is placed into the above set-back pin hole. Assembly of the modular segmented retaining wall is described in more detail below. Set-back receiving slot  114  and vertical receiving slot  118  have the same depth as receiving slots  94  and  98  of masonry block  18  ( FIG. 8 ). Preferably, set-back receiving slot  114  and vertical receiving slot  118  are 1¼ inches deep. 
   Vertical pin holes  116  are identical to vertical pin holes  66  of masonry block  16  ( FIG. 8 ). Vertical receiving slot  118  is similar to receiving slots  68 A and  68 B of block  16  except that it is a single channel extending from sidewall  108  to sidewall  110  across top surface  104 . Vertical pin holes  116  are horizontally aligned with set-back pin holes  112 . Vertical pin holes  116  partially project through vertical receiving slot  118  so that the center of vertical pin holes  116  is positioned ¼ inch forward of the center line of vertical receiving slot  118 . Masonry block  20  is preferably made from high-strength, low-absorption concrete on standard block molding machines. Preferably, masonry block  20  is 6 inches high and its front face  100  is 8 inches wide. 
   In another embodiment, modular retaining wall  10  uses three types of “weathered” masonry blocks. Weathered masonry blocks are simply masonry blocks  16 ,  18 , and  20 , as described above, which have been tumbled in block tumbling equipment. The tumbling process strips away corners, edges and the finished look of masonry blocks  16 ,  18 , and  20 . Weathered versions of masonry blocks  16 ,  18 , and  20  look more like natural stone, and a wall constructed of weathered masonry blocks resembles a wall of random sized natural stone. 
   Universal Retaining Pin 
     FIGS. 11A ,  11 B, and  11 C illustrate the retaining pin of the present invention. Universal retaining pin  130  includes core member  132 , lower section  134 , upper section  136 , flanges  138  and ribs  140 ,  142  and  144 . Lower section  134  further includes distal end  146  and proximal end  148 , and upper section  136  further includes distal end  150  and proximal end  152 . 
   Core member  132  of pin  130  extends from distal end  146  of lower section  134  to proximal end  152  of upper section  136  along the central axis of pin  130 . Core member  132  has a square cross section and forms the base of pin  130 . Flanges  138  extend radially from core member  132  and extend along the entire length of pin  130  from distal end  146  of lower section  134  to proximal end  152  of upper section  136 . Flanges  138  are integrally formed with core member  132 . Preferably, there are four flanges  138 , extending radially from core member  132  at right angles with respect to one another. At distal end  146  of lower section  134 , ends  153  of flanges  138  taper upwardly from core member  132 . 
   At distal end  150  of upper section  136 , each flange  138  includes notch  154  so that end  155  of each flange  138  tapers upwardly from core member  132 . Notches  154  allow upper section  136  to be sheared off from pin  130  leaving only lower section  134 . Preferably, flanges  138  project approximately ¼ inch from core member  132 . 
   Ribs  140 ,  142  and  144  are disc shaped members extending from and encompassing core member  132 , as well as mating with flanges  138 . Ribs  140 ,  142  and  144  are integrally formed with core member  132  and flanges  138  and are aligned perpendicular to core member  132  and flanges  138 . Core member  132  and flanges  138  are co-axial elongated members, whose shared axis runs through the center of disk shaped ribs  140 ,  142 , and  144 . Ribs  140 ,  142  and  144  provide stiffness to pin  130  and help counteract shear forces exerted on pin  130  by the masonry blocks. 
   Universal retaining pin  130  is used to secure masonry blocks in succeeding courses of segmented retaining wall  10  of the present invention. Pin  130  also helps provide consistent alignment of masonry blocks. During installation, pin  130  is inserted into a pin hole of a first masonry block. Pin  130  drops through the first block and into an underlying block. A section of pin  130  is positioned within the underlying masonry block and another section remains in the first block. 
   For ease of installation, pin  130  is long enough to extend from the bottom of the receiving slot of the underlying block to nearly the top surface of the block above. However, pin  130  cannot protrude above the top surface of the upper block, where it was inserted. If pin  130  is too long, it interferes with installation of additional courses of retaining wall  10 . Because the present invention uses masonry blocks of varying heights, universal retaining pin  130  has an adjustable length. When universal retaining pin  130  is inserted into masonry block  18 , which has a smaller height than masonry blocks  16  and  20 , upper section  136  of pin  130  is removed, shortening the length of pin  130  so that it will not protrude through top surface of masonry block  18 . 
   Preferably, universal retaining pin  130  is a non-corrosive, nylon/fiberglass composite. Ribs  140 ,  142  and  144  are ½ inch in diameter. Rib  140  is spaced 2⅛ inches from distal end  146  of lower section  134 . Rib  142  is positioned at proximal end  148  of lower section  134 , and rib  144  is located at proximal end  152  of upper section  136 . Pin  130  is 6¾ inches long, with lower section  134  being 4⅝ inches long and upper section  136  being 2⅛ inches long. 
   Assembly of the Modular Wall 
     FIG. 12  is a perspective view of a portion of segmented retaining wall  10  with parts of the wall removed to illustrate its construction. Retaining wall  10  is built by stacking masonry blocks and using pins to secure the masonry blocks in place. Initially, an installer conducts standard landscape preparation for construction of a segmented retaining wall including excavating (not shown), preparing a leveling pad (not shown), and placing a base course (not shown). The base course (not shown) typically consists of uniform blocks laid to form a level, smooth base course. Then, the installer begins construction of the modular wall on top of the base course. 
   Retaining wall  10  is constructed one module at a time. Modules are constructed along a row creating a modular row. After a first modular row is completed, the next modular row is laid on top of the first row, one module at a time. 
   To construct each module, an installer first positions a bottom course of that module, which contains either two masonry blocks  18 , three masonry blocks  20 , or a combination of one masonry block  16  and one masonry block  20 . Next, the installer completes that module by positioning a top course of blocks over the bottom course. The top course includes masonry blocks that are aligned corresponding to one of modules  22 A– 22 F. (See  FIGS. 2–7 ). Preferably, masonry blocks of bottom course are secured to blocks of the base course with pins  130 . 
   After constructing one module, an adjacent module is constructed in the same manner starting with its bottom course. Adjacent modules are positioned along the length of wall  10  without being interconnected, forming a first modular course  160  of wall  10 . (See  FIG. 12 ). First modular course  160  has one uniform height along the length of wall  10 , although within first modular course  160  the top courses and the bottom courses of the individual modules may vary in height. 
   An installer does not need to predetermine the layout of modules  22 A– 22 F within the modular courses. All modules  22  have the same external dimensions, and for the purpose of constructing modular wall  10 , are interchangeable. Thus, the installer can simply decide in the field (at the time of wall installation) which module  22 A– 22 F will be built adjacent the previous module  22 . 
   Preferably, second modular course  162  (see  FIG. 12 ) is installed over first modular course  160  with a variable bond. With a variable bond, modules  22  of second modular course  162  do not need to be placed either exactly over or exactly halfway over underlying modules  22  of first modular course  160 . Modules  22  of second modular course  162  are horizontally offset from underlying modules  22 , and each module  22  of the second modular course  162  overlaps two underlying modules  22 . Thus, masonry blocks from bottom course  26  of a module  22  in second modular course  162  are secured with pins  130  to underlying masonry blocks from top course  24  from two adjacent modules  22  in first modular course  160 . 
   Second modular course  162  is installed in the same manner as the first. Each module  22  is installed over first modular course  160 , starting with its bottom course  26  followed by its top course  24 . Adjacent modules  22  are installed along the length of wall  10  forming second modular course  162 . Additional modular courses (not shown in  FIG. 12 , but see  FIG. 1 ) are constructed in the same fashion. The resultant modular retaining wall  10  has the appearance of a random pattern stone wall, typical of natural stone. In certain conditions, depending on wall height and properties of the soil, a wall may need geosynthetic soil reinforcement for additional stability and reinforcement. Such soil reinforcement techniques are well known in the art. 
   Preferably, two retaining pins  130  are used to secure each masonry block to underlying masonry blocks. Preferably, pins  130  are placed in the two outer most pin holes of each block (e.g., pin holes  62 A and  62 D of block  16 , pin holes  92 A and  92 D of block  18 , and pin holes  112 A and  112 B of block  20 ). If one of the outside pin holes does not align with an underlying receiving slot, then the next closest pin hole is used. 
   More specifically, the unique designs of masonry blocks  16 ,  18 , and  20  and universal pins  130  provide greater convenience for construction of the modular retaining wall of the present invention. The masonry blocks of top course  24  of a module  22  are positioned over underlying masonry blocks so that pinholes of the above blocks align with the appropriate receiving slots (depending on the desired amount of canting of the retaining wall) of the underlying blocks. Universal pins  130  are inserted into pin holes and drop through the pin holes and into receiving slots of the underlying masonry blocks. If pin  130  stops upon reaching the top surface of the underlying masonry block, then the overlying block must be slightly readjusted to position the pin hole directly over the underlying receiving slot, at which point pin  130  will drop into the receiving slot. Retaining pins  130  are pressed firmly into pin holes to assure that they are fully seated in the receiving slot of the underlying masonry blocks. 
   Retaining pin  130  has an adjustable length because it is used to secure blocks of different heights. During installation, a fully seated pin must extend to near the top of the pin hole without protruding from it, to enable the installer to ascertain whether the pin is properly inserted into a receiving slot. A pin that is too long will protrude from the block surface and interfere with the installation of the next course, while a pin that is too short will drop into a pin hole and “disappear” into the block without indicating whether it entered the underlying receiving slot. A properly sized pin will disappear into the pin hole only when properly fully seated. If the pin is not seated into an underlying receiving slot, the properly sized pin protrudes from the top of the pin hole to alert the installer. 
   The adjustable length of universal pin  130  allows an installer to use only one style of retaining pin while working with masonry blocks of differing heights. With respect to masonry blocks  16  and  20 , which have a larger height than masonry block  18 , the entire universal pin  130  is used. However, with respect to masonry block  18  only lower section  134  of universal pin  130  is used. When universal pin  130  is used to secure masonry block  18 , the entire pin  130  is inserted into one of the pin holes  92  or  96 , and once fully seated with its distal end  146  in a receiving slot of the below block, a shear force is applied to upper section  136  of pin  130 . A hammer or other instrument (not shown) can be used to apply the shear force and to break off upper section  136  of pin  130 . 
   For example, in  FIG. 12 , a module  22 A is shown (the lower left-most module) with a portion of masonry block  18  removed. The removed portion of masonry block  18  reveals lower section  134  of universal pin  130  extending through set-back pin hole  92  of block  18  and seated in set-back receiving slot  114  of the underlying masonry block  20 . Proximal end  148  of lower section  134  is positioned near top surface  84  of masonry block  18  and does not extend above the plane defined by top surface  84 . During installation, upper section  136  of universal pin  130  was removed, leaving only lower section  134 . 
   However, in a module  22 B in  FIG. 12  (the upper right-most module), masonry block  16  is shown with a portion thereof removed, exposing an inserted pin  130  including lower section  134  and upper section  136 . The removed portion of masonry block  16  reveals that both sections  134  and  136  of the universal pin  130  extend through set-back pin hole  62  of block  16  and that lower section  136  is seated in set-back receiving slot  94  of the underlying masonry block  18 . Proximal end  152  of upper section  136  is positioned near top surface  48  of masonry block  16  and does not extend above the plane defined by top surface  48 . Masonry block  16  has a greater height than masonry block  18 , so the entire length of universal pin  130  is necessary for its proper and convenient installation. 
   Variable Canting of the Modular Wall 
   As described above, masonry blocks of retaining wall  10  can be used to build canted walls or nearly vertical walls.  FIGS. 13 and 14  illustrate this unique feature of the present invention. For canted walls, masonry blocks of the present invention are positioned so that their respective set-back pin holes are aligned over the set-back receiving slots of the underlying blocks. The amount of set-back is determined by the distance from the set-back pin hole to the set-back receiving slot. For near-vertical alignment, masonry blocks of the present invention are positioned so that their respective vertical pin holes are aligned over the vertical receiving slots of the underlying blocks. Vertical pin holes are slightly offset from vertical receiving slots to allow for a slight initial canting. However, once backfill is applied during construction, pressure from the backfill pushes the masonry blocks forward, and the resulting wall is nearly vertical. 
     FIG. 13  illustrates a side view of a canted retaining wall  170  having a preferred set-back alignment.  FIG. 14  illustrates a side view of a near-vertical retaining wall  180  constructed with the same masonry blocks used in retaining wall  170  of  FIG. 13  (the same blocks are used in the two walls  170  and  180  to best illustrate this unique variable canting feature of the masonry blocks of the present invention). For simplicity, retaining walls  170  and  180  of  FIGS. 13 and 14 , respectively, are shown with only six courses of blocks and without a cap stone. 
   Canted retaining wall  170  includes masonry block  20 A secured over masonry block  18 A. Masonry block  18 A is secured over masonry block  18 B. Masonry block  18 B is secured over masonry block  16 A. Masonry block  16 A is secured over masonry block  18 C. Masonry block  18 C is secured over masonry block  16 B. Near-vertical retaining wall  180  of  FIG. 14  is constructed from the same combination of masonry blocks  20 A,  18 A,  18 B,  16 A,  18 C, and  16 B. Masonry block  20 A refers to like-shaped masonry block  20  from  FIGS. 10 ,  10 A and  10 B. Masonry blocks  18 A,  18 B, and  18 C are like-shaped masonry blocks  18  from  FIGS. 9 ,  9 A and  9 B. Masonry blocks  16 A and  16 B are like-shaped masonry blocks  16  from  FIGS. 8 ,  8 A and  8 B. 
   As shown in  FIG. 13 , set-back pin hole  112  of block  20 A is aligned with underlying set-back receiving slot  94  of block  18 A, and universal pin  130  is seated within the aligned channel. As described above, universal pin  130  used to secure the higher masonry block  20  comprises both lower section  134  and upper section  136 . In the next-lower course, set-back pin hole  92  of block  18 A is aligned with the underlying set-back receiving slot  94  of block  18 B, and universal pin  130  is seated within the aligned channel. Universal pin  130  that is used to secure the shorter masonry block  18 A has had its top section  136  sheared off, and thus only includes lower section  134 . 
   In the next-lower course, set-back pin hole  92  of block  18 B is aligned with the underlying set-back receiving slot  64  of block  16 A, and universal pin  130  is seated within the aligned channel. Universal pin  130  seated within masonry block  18 B has had its top section  136  sheared off. In the next-lower course, set-back pin hole  62  is aligned with the underlying set-back receiving slot  94  of block  18 C, and universal pin  130  is seated within the aligned channel. Universal pin  130  used to secure masonry block  16 A comprises both lower section  134  and upper section  136 . In the second lowest course, set-back pin hole  92  of block  18 C is aligned with the underlying set-back receiving slot  64  of block  16 B, and universal pin  130  is seated within the aligned channel. Universal pin  130  seated within block  18 C has had its upper section  136  sheared off. 
   The same combination of masonry blocks  20 A,  18 A,  18 B,  16 A,  18 C, and  16 B is used to build a near-vertical retaining wall as illustrated in  FIG. 14 . In the top course, vertical pin hole  116  of block  20 A is aligned with the underlying vertical receiving slot  98  of block  18 A, and universal pin  130  is seated within the aligned channel. Universal pin  130  used to secure the higher masonry block  20 A comprises both lower section  134  and upper section  136 . Because vertical pin hole  116  is only slightly spaced forward of vertical receiving slot  118 , a portion of the seated universal pin  130  is seated within vertical receiving slot  118 . 
   In the next-lower course, vertical pin hole  96  of block  18 A is aligned with the underlying vertical receiving slot  98  of block  18 B, and universal pin  130  is seated within the aligned channel. Universal pin  130  seated within block  18 A has had its upper section  136  sheared off. In the next-lower course, vertical pin hole  96  of block  18 B is aligned with the underlying vertical receiving slot  68  of block  16 A, and universal pin  130  is seated within the aligned channel. Universal pin  130  seated within block  18 B has had its upper section  136  sheared off. In the next-lower course, vertical pin hole  66  of block  16 A is aligned with the underlying vertical receiving slot  98  of block  18 C, and universal pin  130  is seated within the aligned channel. Universal pin  130  seated within block  16 A comprises both lower section  134  and upper section  136 . In the second lowest course, vertical pin hole  96  of block  18 C is aligned with the underlying vertical receiving slot  68  of block  16 B, and universal pin  130  is seated within the aligned channel. Universal pin  130  seated within block  18 C has had its upper section  136  sheared off. 
   As demonstrated by walls  170  and  180  of  FIGS. 13 and 14 , masonry blocks  16 ,  18  and  20  of the present invention can be used to build walls of varying slope by aligning respective pin holes with underlying receiving slots. A manufacturer can further vary the cant by manufacturing blocks with differing distances between pin holes and their respective receiving slots, therefore either increasing or decreasing the slope of the wall. Furthermore, a wall can be constructed with a varied slope throughout its height. During construction, certain masonry blocks-or modules are secured along the near-vertical alignment, while other masonry blocks or modules are secured along the set-back or canted alignment. So that certain blocks, modules, or courses will be nearly vertical and others will be canted. 
   Although the preferred embodiment of the present invention described masonry blocks that are secured by pins, other securing or interlocking methods for mortarless masonry blocks are known in the art. Masonry blocks of the present invention can be manufactured with securing extensions such as feet, lips or flanges (and, if desired, associated recesses) for use in constructing the modular segmented wall of the present invention. Additionally, although the preferred embodiment included receiving slots, other receiving apertures are contemplated. Receiving apertures can very in size, shape, and depth, and a modification of the receiving aperture might require a modified securing pin consistent with the teachings of this invention. Furthermore, although the preferred embodiment described a retaining wall, the techniques of the present invention are equally applicable to any wall structure such as a free-standing wall, or the face of a building or a bridge. 
   Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes maybe made in form and detail without departing from the spirit and scope of the invention.