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This application claims benefit of provisional application No. 60,083,671 filed Apr. 30, 1998. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     This invention relates to a modular masonry step and deck assembly for entering an elevated entrance to a building, the assembly including a plurality of dry stacked like-shaped risers and a plurality of like-shaped treads that can be assembled into a variety of shapes, sizes and heights to provide a custom fit for a variety of buildings, each tread having one of a few designs on its surface that combine to produce a continuous, integrated design. 
     BACKGROUND OF THE INVENTION 
     Foundations and entrances of buildings are typically elevated above ground level. Steps and a deck or stoop are provided to allow a person to walk or climb up to or near the level of the threshold of the door. Each step has a given rise and a given depth to allow the person to safely negotiate the step. A series of steps requires a certain amount of surface area in front of the door. The deck or stoop forms a platform with enough surface area for a person to safely open and enter or exit through the door. The size and shape of the available area for constructing the steps and deck varies due to obstructions, such as the building foundation, adjacent structures, driveways, walkways, trees, bushes and gardens. Other considerations, such as the locations of widows, mail boxes and sitting areas can also affect the location, size and shape of the step and deck construction. 
     A variety of approaches have been developed for constructing steps and decks leading into building. While some of these approaches provide flexible constructions that are easily adapted to the size and shape of a specific area, they lack durability and maintainability. Other approaches provide constructions that are durable and easy to maintain, but lack the flexibility to adapt to a variety of applications. These constructions can also be difficult to alter or remove. Providing a continuous, integrated design in the surface of conventional step and deck constructions creates further problems for conventional approaches. 
     Wooden step and deck assemblies are flexible and can be custom fit to the contours of a specific building, mobile home or trailer and its landscaping. A problem with wooden step and deck constructions is that they lack long term durability and require frequent upkeep due to the loosening of nails, screws, bolts or other fixtures, as well as the need for routine applications of weather inhibitors to slow down rotting caused by rain, wind, snow and ice. Additional types treatments are used to reduce the rate of deterioration of the wood resulting from the constant wear and tear of use, salt, gravel, dirt and even snow and ice removal. The smooth and frequently slippery surface of lacquered wood requires the use of anti-skid mats or strips to be applied to the walking surfaces. In addition, wooden step and deck constructions are typically anchored by several posts or supports embedded in the ground. These posts or supports can shift and heave over time, especially in regions subject to frequent freezing and thawing. Digging up and resetting these post or supports can be difficult and labor intensive, particularly in the cramped areas next to the building and its landscaping. 
     Precast concrete step and deck constructions are typically more durable and require less upkeep than wooden assemblies. However, the large slabs that form the steps and decks are heavy to lift and move, and difficult to align during installation. Motorized construction equipment or special tools are usually required. For cost reasons, manufacturers tend to massproduce a limited selection of precast step and deck slabs, each slab having a specific shape and size. The limited selection is frequently unable to conform to the size and shape of the area allocated for the step and deck construction. While custom precast concrete step and deck slabs are possible, the manufacturing and shipping costs result in significantly greater unit prices. Moving, removing, altering or adding to a large precast step or deck construction can also be labor intensive and expensive. 
     Poured concrete step and deck constructions conform to the specific building and landscape design. However, these constructions require the time and expense of building forms and the delivery or mixing of the concrete. Special layout, carpentry, and concrete finishing skills are also required. Poured concrete steps and decks are also prone to cracking due to the settling or freezing and thawing of the ground supporting the steps and deck. The removal or replacement of these larger poured concrete slabs can also be prohibitive. Again, large construction equipment can be required. As with precast constructions, removing, altering or adding to the precast construction can be labor intensive and expensive should the owner want to move, expand or add a handicap access ramp to the construction. 
     While dry stacked constructions have been developed to form retaining walls and building walls, the instability of a multi-column, multi-row, multi-tier dry stacked assembly has inhibited its adoption in step and deck constructions. Even a single column wall system will utilize a mechanism for securing the risers together. For example, many retaining wall systems utilize a projection extending from the lower surface of the block to grip the block beneath it. A variety of hardware fastening systems can also be used to secure the single column of blocks together. Retaining wall constructions typically stagger the blocks laterally from tier to tier to form a running bond construction that increases the strength of the wall. Each tier or course of blocks is also set back from its lower tier so that the wall leans into the hill it is retaining. While a staggered running block construction utilizing a set back is appropriate for a dry stacked retaining wall construction, such attributes render the blocks inappropriate for a step and deck assembly. 
     Some conventional warehouse wall constructions utilize a column of dry stacked blocks between poured concrete pillars. A fiberglass reinforced plastered sheet is placed on each side of the dry stacked blocks to keep them in place. The expense of forming poured concrete pillars and applying reinforced plaster sheets renders such a construction inappropriate for a step and deck assembly. Pouring concrete down the hollowed out cores of the dry stacked blocks to hold them in place is also known. However, such constructions include the expense of a significant amount of concrete, as well as the mess of mixing and filling the cores of the stacked blocks. Such constructions are also difficult to remove or alter. 
     Incorporating a continuous, integrated pattern into the walking surface of a masonry step and deck construction further complicates its design. While a precast step and deck slab construction can incorporate a pattern on its surface, these patterns make it even more difficult to integrate two separate slabs. Poured concrete constructions require a skilled mason to form the design into the concrete while it is setting, which further adds to the cost and inconvenience of such constructions. Extending the continuous pattern into the walkway leading to the steps and deck creates further problems. Precast concrete steps and decks are not sized or shaped to create walkways. Poured concrete walkways with hand formed designs add to an already expensive construction technique. 
     The present invention is intended to solve these and other problems. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention relates to a modular masonry step and deck assembly consisting of a plurality of like-shaped risers and a plurality of like-shaped treads that enable the assembly to have a variety of shapes, sizes and heights to provide a custom fit to a variety of buildings, mobile homes or trailers. The risers are dry stacked in a multi-tier, multi-column, multi-row arrangement to form a base of the assembly. An inwardly expanding groove is formed in each corner of each riser. When aligned flush with adjacent risers and dry stacked one atop the other in a stacked bond arrangement, the groves form a continuous vertical channel. A semi-flexible locking key is formed inside the channel to secure the risers together, but accommodate movements caused by the freezing and thawing of the ground. Four differently shaped treads are used to form the walking surface of the step and deck assembly. Each tread shape is used to form a specific portion of the walking surface. A plurality of each like-shaped tread is used to form its specific portion of the walking surface to create a continuous lip around the perimeter of the steps and deck. Each of the four like-shaped treads has a specific design on its top surface to form an integral, continuous pattern on the steps and deck. The treads can be used to continue the design into a walkway. 
     One advantage of the present masonry step and deck assembly is that the modular structure of its components provides the flexibility to produce a customized fit to accommodate the size and shape of the available area for various buildings. The number of tiers, rows and columns of risers forming the base of the assembly can be varied to accommodate the height of the door, the shape of the building foundation, adjacent structures, driveways, walkways, and landscaping, such as trees, bushes and gardens. The step and deck assembly can also be constructed to accommodate the locations of widows, mailboxes and sitting areas. The modular construction also allows the components to be sized so that a homeowner can lift and align them by themselves without the aid of motorized equipment or special tools. 
     A further advantage of the present masonry step and deck assembly is that the semi-flexible locking keys permit a degree of movement between adjacent risers. This gives the unitary base the ability to absorb movements in the ground caused by freezing and thawing. No mortar is needed which would inhibit the flexibility of the base and crack over time. Instead, the semi-flexible keys continue to hold the risers together to form the unitary base even when the risers are moved out of direct flush contact with their adjacent risers. The flexible keys also allow the risers to move back into direct flush contact when the ground settles back to its unfrozen condition. Instead of using embedded posts, the entire unitary base can be said to float on the ground. 
     Another advantage to the present masonry step and deck assembly is its durability and relatively maintenance free upkeep. The masonry treads are capable of handling heavy traffic for over relatively long periods of time without showing signs of war and tear, even when subjected to salt, gravel, dirt, and snow and ice removal. No nails, screws or bolts need to be tightened. Weather inhibitors and other protective coatings are not necessary to prevent or reduce the rate of deterioration of the masonry components. 
     A still further advantage of the present masonry step and deck assembly is that it enables a home owner to easily customize the step and deck assembly to fit their specific home, identify and procure the necessary components, and install the assembly. No, special layout, carpentry, and concrete finishing skills are also required. No forms need to be built, and no concrete needs to be delivered or mixed. The unitary base is constructed entirely of whole risers. No splitting of risers is required as in a staggered running bond arrangement. 
     A still further advantage to the present masonry step and deck assembly is that its modular design is readily disassembled for moving to a new location or discarded. The assembly can also be altered or additional sections can be added to enlarge the step and deck assembly. Moving and modifying the assembly can be done by an individual homeowner without the need of motorized equipment or special tools. The assembly can be easily removed from a tight area without disturbing the surrounding. Once installed the design can be readily altered or expanded as desired, such as to add a handicap access ramp. 
     A still further advantage to the present masonry step and deck assembly is the limited number of differently shaped components that are required to complete any size, shape or height. Only a single riser and four treads are required to construct a wide variety of step and deck designs. This limited number of components provides significant economies in the manufacturing, distribution, retail sales, construction, and repair or redesign of the assembly. During manufacture, there are fewer forms to design, maintain and store. Fewer manufacturing set ups and down times are required to produce a complete assembly. Fewer risers and treads need to be maintained in inventory and tracked during shipping. These savings are again realized at the retail level, where space is limited and expensive. The limited number of components also assists the home owner in designing, hauling and constructing a deck and step assembly for their home. 
     A still further advantage of the present masonry step and deck assembly is that the treads form a continuous lip around the steps and deck. The lip increases the depth dimension of each step, without requiring an increase in the depth dimension of the risers. The narrower the risers, the more possibilities there are to vary the overall depth of the unitary base. This improves the overall flexibility of the step and deck assembly and the ability to achieve a custom fit for a particular home or building. 
     A still further advantage to the present masonry step and deck assembly is that the treads provide grooves near the outer edges of each step. These grooves provide traction for a person walking up or down the steps. 
     A still further advantage to the present masonry step and deck assembly is that it incorporates a continuous, integrated pattern on the walking surface of a step and deck assembly. Each of the four differently shaped treads has a different pattern of grooves formed into its upper surface. The grove pattern is dependent on the specific portion of the walking surface in which it is placed, and the intended overall design of the step and deck assembly. By placing each tread in its specific portion of the assembly, the design of each tread will be integrated with the design of the treads placed in adjacent portions of the assembly. The treads can also be used to form a walkway. Accordingly, the continuous, integrated pattern can be extended from the surfaces of the steps and deck to include the walkway as well. 
     Other aspects and advantages of the invention will become apparent upon making reference to the specification, claims and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the modular masonry step and deck assembly having three tiers, four rows and six columns to provide a custom fit for a specific house, and with its continuous design extending across the walking surface of the assembly and down a walkway. 
     FIG. 2 is a perspective view of a first embodiment of a riser with a light slot formed in one longitudinal wall and a wiring notch in the opposite longitudinal wall. 
     FIGS. 3A-E are perspective, front plan, side plan, rear plan and top views of a second embodiment of the riser with a light slot formed in one longitudinal wall and a vertical groove with an inwardly expanding cross-sectional area formed in each vertical corner. 
     FIG. 4 is a perspective view of a semi-flexible, locking key having a crossectional area with a clover-like shape. 
     FIG. 5 is a top view of a clover-shaped locking key inserted into a channel formed by four flushly aligned risers with their side wall surfaces in direct contact. 
     FIG. 6 is a top view showing a third embodiment of the riser with a light slot formed in one longitudinal wall and a groove having an inwardly expanding cross-sectional area formed at the central point of the other three walls. 
     FIG. 7 is a perspective view of a semi-flexible, locking key having a crossectional area with an hourglass-like shape. 
     FIG. 8 is a top view of an hourglass-shaped locking key inserted into a channel formed by two flushly aligned risers with their side wall surfaces in direct contact. 
     FIGS. 9A-D are perspective, front plan, side plan and top views respecively of a corner tread having a pair of parallel grooves formed into its upper surface along three of its edges. 
     FIGS. 10A-D are perspective, front plan, side plan and top views respectively of a front tread having a pair of parallel grooves formed into its upper surface near two opposed edges. 
     FIGS. 11A-D are perspective, front plan, side plan, and top views respectively of a side tread having a pair of parallel grooves formed into its upper surface near one of its edges. 
     FIG. 12 is perspective view of an inner tread having a smooth surface. 
     FIGS. 13A-D are perspective, front plan, side plan, and top views respectively of a corner tread having an alternate design with a pair of parallel grooves formed into its upper surface along two of its edges. 
     FIG. 14 is a perspective view of a partially assembled step and deck assembly showing the placement of the risers and treads and the injection of a foam spray to form one of the semi-flexible locking keys. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While this invention is susceptible of embodiment in many different forms, the drawings show and the specification describes in detail a preferred embodiment of the invention. It should be understood that the drawings and specification are to be considered an exemplification of the principles of the invention. They are not intended to limit the broad aspects of the invention to the embodiment illustrated. 
     FIG. 1 shows a house  5  with a concrete foundation  6 , walls  7  and a door or entrance  8 . The door  8  has a threshold  9  elevated a specific height above the level of the ground  10  in an area  15  in front of the door. Several obstructions are located around the door  8 . These obstructions include a tree  21  located to the left of the door  8 , a garden  22  located to the right, a walkway  23  leading to a driveway  24  in front of the house, and the foundation  6  located directly beneath the door 8 . The house  5  also includes structural features such as a window  26  located to the right of the door  8  and a mailbox  28  located to the left. These obstructions and features define the usable area  15  for constructing a step and deck constructions, such as the modular step and deck assembly identified as reference number  30 . While the building is shown to be a house setting on a foundation, it should be understood that the building could also be a mobile home or a portable trailer such as the type found on a construction site. 
     The modular masonry step and deck assembly  30  includes a unitary base  31  and a walking surface  32 . The assembly  30  has a lower surface  34  that rests on the ground  10 , and a rear surface  35  that abuts a planar surface of the foundation  6  below the door  8 . The assembly  30  has a step portion  36  that includes a plurality of steps  37  located in front of the door  8 , and a deck portion  38  located proximal the door. Although the step portion  36  is shown in front of the door  8  with the deck portion  38  in between, it should be understood that the assembly could be constructed with the step portion located to the right or left of the door. 
     The unitary base  31  is formed by a plurality of like-shaped risers  50 . The risers  50  are formed of a high strength cementitious material, such as concrete formulated to ASTM specification C-936. Concrete of such specification is designed for use as interlocking paving blocks and has a strength of 8,000 psi. The risers  50  can take several different forms as shown in FIGS. 2,  3  and  6 . Each embodiment  51 ,  52  or  53  of the riser  50  includes a main body  61  having a planar top surface  62  that is parallel to its planar bottom surface  63 . The risers  51 - 53  also includes four side walls  64 - 67 , which for the purpose of clarity may be referred to as the front wall  64 , rear wall  65  and opposed side walls  66  and  67 . The front and rear or longitudinal walls  64  and  65  are longer than the side or transverse walls  66  and  67  to give the riser its rectangular shape. 
     Each side wall  64 - 67  of the riser  50  has a planar outside surface  71 - 74 . Each outside surface  71 - 74  intersects its adjacent outside surfaces and the top and bottom surfaces  62  and  63  at a right angle. The outside surfaces  71  and  72  of front and rear walls  64  and  65  are parallel, as are the outside surfaces  73  and  74  of side walls  66  and  67 . These parallel surfaces  62 - 67  give the rectangular riser  50  a uniform height dimension of about  8  inches from top to bottom  62  and  63 , a uniform width dimension of about 15 and ⅝ inches from side to side  66  and  67 , and a uniform depth dimensions of about 9 and ⅝ inches from front to rear  64  and  65 . The outside surfaces  71 - 74  of the risers have a decorative pattern (not shown) consisting of many closely spaced vertical corrugated ridges. The side walls  64 - 67  have inside surfaces  76 - 79  that define a hollow inner core  80  that passes completely through the riser  50 . 
     As shown in FIG. 2, the first embodiment  51  of riser  50  includes a first slot  82  for holding a light fixture (not shown). The slot  82  is formed into the top surface  62  of the riser  51  at the center of the front wall  64 . The slot  82  has a sloped lower surface that produces a larger recess in the outer surface  71  and a smaller recess in the inside surface  76 . A notch  83  is formed in the inside recess to accommodate a wire (not shown) of the light fixture. A second slot  85  is located in the top surface  62  toward the center of the rear wall  65 . A notch is formed in the lower surface of the slot  85  for routing the electrical wire to the light fixture. Adjacent outside surfaces  71 - 74  meet to form the vertical corners  90  of the riser  51 . 
     The second embodiment  52  of the riser  50  is shown in FIGS. 3A-E. Riser  52  includes the slot  82  for the light fixture, but omits slot  85 . The electrical wires can be routed down through the inner core  80  of the riser and underground. Vertical grooves  100  are formed into the corners  90  of the riser  52 . Each groove  100  has an inwardly expanding cross-sectional shape  101  formed by an arcuate shaped wall  102  having a narrow neck  104  near the surfaces  71 - 74  of the riser  52  and a wider circular inner portion  106  formed in the walls  64 - 67 . Each groove  100  maintains this uniform cross-sectional shape  101  as it spans from the top  62  to the bottom  63  surface of the riser  52 . When four risers  52  are aligned in a side-by-side arrangement with their outside surfaces  71 - 74  aligned flush and in direct contact as in FIG. 5, the corner grooves  100  of the risers combine to form a single channel  110  with a cloverleaf-shaped cross-sectional area, each leaf being formed by one groove of each riser. 
     The third embodiment  53  of the riser  50  is shown in FIG.  6 . Riser  53  also includes the slot  82  for the light fixture, but omits slot  85 . Vertical grooves  120  are formed along the center points of both rear wall  65  and side walls  66  and  67 . Each groove  120  has an inwardly expanding cross-sectional shape  121  formed by angled walls  122  that come together near the surfaces  72 - 74  of the riser  53  to form a narrow neck  124 , and a widening trapezoidal shaped inner portion formed in the walls  65 - 67 . Each groove  120  maintains this uniform cross-sectional shape  121  as it spans from the top  62  to the bottom  63  surface of the riser  53 . When two risers  53  are aligned in a side-by-side arrangement with their outside surfaces  71 - 74  aligned flush and in direct contact as in FIG. 8, the grooves  120  combine to form a single channel  130  with an hourglass-like cross-sectional shape, each half of the hourglass being formed by one groove  120  of each riser. 
     The risers  50  are dry stacked to form several tiers  150 . The tiers  150  include a ground tier  152  and several stacked tiers  154 , including an upper tier  156 . Each tier  150  is arranged into multiple rows  160  and multiple columns  162  of risers  50 . Each tier has the same number of rows  160 , but the ground tier  152  has the largest number of columns  162 . Each stacked tier  154  is placed atop an immediately lower tier  164 . Each tier  150  has a pair of opposed end rows  165  and  166  and a front column  168 . Each stacked tier  154  has one fewer columns  162  than its immediately lower tier  164 . The stacked tier  154  is staggered from the front column  168  of its immediately lower tier  164 . 
     Each of the front columns  168  has two opposed corner risers  170 , and a remaining front portion  172  that includes two more risers. The end rows  165  and  166  of the upper tier  156  includes a corner riser  170 . The end rows also include a remaining side portion  174  that includes three more risers. The upper tier also has an interior portion  176  of risers  50 . The rear surface  35  of the assembly  30  is formed by the tiers  150 . This rear surface  35  forms a common planar surface  178  adapted for alignment with the foundation  6  of the building  5 . 
     The risers  50  forming the unitary base  31  are dry stacked in a stacked-bond arrangement, each stacked riser  50  setting directly atop another. The side wall surfaces  71 - 74  of each stacked riser  50  is in coplanar alignment with the side wall surfaces  71 - 74  of the riser on which it is stacked. Adjacent risers  50  in the same tier  150  are aligned in a side-by-side arrangement with their outside surfaces  71 - 74  in aligned flushly and in direct contact as in FIG.  5 . The corner grooves  100  of the risers  150  combine to form the cloverleaf-shaped channel  110 . Because of the stacked-bond arrangement of the risers  50 , each channel  110  formed by four adjacent risers of a given tier  150  is aligned with the channel  110  formed by the four adjacent risers upon which they are stacked. Accordingly, the channels  110  of each tier  150  combine in a linear manner to form a continuous channel  130 . 
     A plurality of elongated locking keys  201  or  202  of the type shown in FIGS. 4 and 7 are used to secure the tiers  150 , rows  160  and columns  162  of risers  50  together to form the unitary base  31 . These locking keys  200  are made of a semi-flexible material. While generally maintaining its shape to secure the risers  50  in place, the semi-flexible keys  200  will bend and stretch to a limited degree. The limited amount of bending and stretching allows the risers  50  forming the unitary base  31  to move slightly with respect to each other. 
     A clover-shaped locking key  201  is used with risers  52  having a vertical groove  100  in the corners of the side walls  64 - 67  as shown in FIG.  4 . An hourglass-shaped key  202  is used with risers  52  having a vertical groove  100  in the center of the side walls  64 - 67  as shown in FIG.  7 . Both keys have a narrow central body portion  204  and an outwardly expanding wider portion or finger  205 . The clover-shaped key  201  has four fingers or lobs  205 . Each finger  205  has a narrow neck portion  210  and a wider outer circular portion  212 . Each finger or lob  205  is shaped to snugly fit into one of the vertical groove  100  of riser  52 . The hourglass-shaped key  202  has a narrow middle portion  220  formed by two parallel walls. Two expanding trapezoidal extensions  222  extend from opposite ends of the middle portion  220 . Each extension  222  has a pair of angled walls  224  that diverge away from the narrow middle portions  220 . extensions  222  extend from opposite ends of the middle portion  220 . Each extension  222  has a pair of angled walls  224  that diverge away from the narrow middle portions  220 . 
     One locking key  201  or  202  is inserted into each continuous channel  130 . Each elongated locking key  200  extends from the bottom surface  63  of the risers  50  forming the ground tier  152 , to the top surface  62  of the risers forming the upper tier  156 . The locking key  200  may also be formed directly in the continuous channels  130  by injecting a foam spray into the continuous channels. When sprayed from a can as shown in FIG. 14, the foam expands to fill the cavity formed by the continuous channel  130 . The foam spray is believed to be made of a polyurethane intermediate which is made up of polymeric diisocyanate polyols and a hydrocarbon gas mixture. 
     As shown in FIGS. 9-12, a plurality of like-shaped corner treads  250 , like-shaped front treads,  260 , like-shaped side treads  270  and like-shaped inner treads  280  are place on the risers  50  to form the walking surface  32 . These treads are made of the same masonry material as the risers  50 . Each tread  250 ,  260 ,  270  and  280  has substantially planar top  251 ,  261 ,  271  and  281  and bottom  252 ,  262 ,  272  and  282  surfaces, and front  253 ,  263 ,  273  and  283 , rear  254 ,  264 ,  274  and  284 , and opposed side  255 ,  265 ,  275  and  285  wall surfaces. Each tread has a uniform height dimension from top  251 ,  261 ,  271  and  281 to bottom  252 ,  262 ,  272  and  282 . Each of these wall surface is substantially at a right angle to its adjacent wall surfaces. 
     As best seen in FIG. 14, each corner tread  250  is placed on the upper surface  62  of one corner risers  170 . Each corner tread  250  has uniform width and depth dimensions that is about one inch greater than the respective width and depth dimensions of the like-shaped risers  50 . Two adjacent side wall surfaces of each corner tread  250  are coplanar with two of the side wall surfaces  71 - 74  of the riser  50  on which it is placed. Each front tread  260  has a uniform width dimension that is equal to the width dimension of the risers  50  and a uniform depth dimension that is equal to said depth dimension of the corner treads  250 . Each of the side treads  270  has a uniform width dimension that is equal to the width dimension of the corner treads  250  and a depth dimension that is equal to the depth dimension of the risers  50 . Each of the front and side treads  260  and  270  has three side wall surfaces that are coplanar to the side wall surfaces of the riser  50  on which they are placed. Each inner tread  280  has uniform width and depth dimensions that are equal to the respective width and depth dimensions of the risers  50 . Each of the side wall surfaces  283 ,  284  and  285  of the inner tread  280  are coplanar with the side wall surfaces  71 - 74  of the riser  50  on which they are placed. 
     The corner treads  250  and front treads  260  combine to form a plurality of steps  290  on the front columns  168  of each tier  150 . One corner tread  250  is placed on each of corner risers  170 . One front tread  260  is placed on each of risers  50  in the remaining front portion  172  of the front column  168 . The side treads  270  and inner treads  280  combine to form a deck  300 . One side tread  270  is placed on each of the risers forming the remaining side portions  174  of the upper tier  156 . One of the inner treads  280  is placed on each of the risers  50  forming the interior portion  176  of said upper tier  156 . The non-coplanar side wall surfaces of the corner  250  and front  260  treads extend outward from their respective risers  50 , and combine to form a continuous lip  310  of about one inch around each of step  290 . The corner  250 , front  260  and side  270  treads form the continuous lip  310  around the step and deck of the upper tier  156 . 
     Parallel grooves  320  are formed into the top surfaces  251 ,  261  and  271  of corner  250 , front  260  and side  270  treads. As shown in FIG. 9A, each like-shaped corner tread  250  has three pairs of grooves  320 . One pair of grooves is formed along each of its front and rear edges as well as one side edge to produce a first design  331 . As shown in FIG. 10A, each like-shaped front tread  260  has two pairs of grooves  320 . One pair of grooves is formed along each of its front and rear edges to produce a second design  332 . As shown in FIG. 11A, each like-shaped side tread  270  has one pair of grooves  320  formed along one of its side edges to produce a third design  333 . As shown in FIG. 12, the like-shaped inner treads have a completely smooth top surface to produce a blank design  334 . Alternated designs are possible for the treads  250 ,  260 ,  270  and  280 . FIGS. 13A-D show a possible alternate design  355  for a corner tread  250 . This alternate design would require the removal of one pair of grooves from the front tread  260 . 
     As shown in FIGS. 1 and 14, the individual designs  331 ,  332 ,  333  and  334  of the treads  250 ,  260 ,  270  and  280  combine to produce a continuous, integral design  340  across the walking surface  32  of the step and deck assembly  30 . By shaping and sizing the treads  250 ,  260 ,  270  and  280  as noted above, placing the different treads in different predetermined locations such as on corner risers  170 , remaining front portions  172 , remaining side portions  174  and inner portions  176 , and forming the grooves  320  at specific spaced locations from the edges of the treads, a continuous, integral design  340  is produced. The grooves  320  of one tread align integrally with the grooves of adjacent treads to produce the continuous design  340 . By placing corner  250  and front  260  treads on the ground  10  in front of the steps  290 , the design  340  can be continued down an associated walkway  23 . 
     As shown in FIG. 14, a bed of gravel  360  is spread on the ground in the usable area  15  adjacent the entranceway  8 . A sheet  365  of construction grade expanded polystyrene can placed over the gravel  360  to provide a stable, flat base for the placement of the ground tier  152  of risers  50 . Risers  50  are then positioned to form the base  31 . The weight of the risers is such that they can be lifted and placed in position by hand. Because the assembly  30  incorporates a dry stacked and stacked-bond riser assembly, the number of tiers  150  determines the total height of assembly  30 , the number of rows  160  determines its total width, and the number of columns determines the total depth. 
     Risers  52  are engaged by pairs of locking key slots to rigidly secure adjacent pairs of risers  90  together. Once the risers  52  have been positioned and locked in engagement with each other by keys  201 , treads  250 ,  260 ,  270  and  280  are adhered to the top surfaces  62  of the risers  50  with an adhesive  350  to complete formation of the step assembly. Preferably, the adhesive should not become rigid upon curing, but should remain somewhat viscous to accommodate for the varying outside temperature conditions that the adhesive will encounter. A preferred adhesive for use in the present invention is a mastic cement, such as that sold under the name “Paverbond”. A set of railings  370  may be secured to the assembly by expandable fasteners  371  placed into openings  372  drilled into the treads of the assembly  30 . 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the broader aspects of the invention.

Summary:
The modular masonry step and deck assembly consists of a plurality of like-shaped risers and a plurality of like-shaped treads that enable the assembly to have a variety of shapes, sizes and heights to provide a custom fit to a variety of buildings, mobile homes or trailers. The risers are dry stacked in a multi-tier, multi-column, multi-row arrangement to form a base of the assembly. An inwardly expanding groove is formed in each corner of each riser. When aligned flush with adjacent risers and dry stacked one atop the other in a stacked bond arrangement, the groves form a continuous vertical channel. A semi-flexible locking key is formed inside the channel to secure the risers together, but accommodate movements caused by the freezing and thawing of the ground. Four differently shaped treads are used to form the walking surface of the step and deck assembly. Each tread shape is used to form a specific portion of the walking surface. A plurality of each like-shaped tread is used to form its specific portion of the walking surface to create a continuous lip around the perimeter of the steps and deck. Each of the four like-shaped treads has a specific design on its top surface to form an integral, continuous pattern on the steps and deck. The treads can be used to continue the design into a walkway.