Abstract:
A piece of furniture such as a standing desk is constructed of intersecting folded prisms provided with a novel slot joint system which affords lateral and torsional stability, simplicity, and long life to such furniture.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation and claims priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 14/664,256, which was filed Mar. 20, 2015, which claims priority under 35 USC §119(e) to provisional U.S. patent application Ser. No. 61/974,039, which was filed Apr. 2, 2014, the entire contents of each of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    This description relates to corrugated furniture design and construction. 
         [0003]    Prolonged sitting is known to have negative health effects. Standing desks are an excellent alternative to sedentary desks as they allow users to work on their feet. Standing while working engages muscles in the back and legs, increases metabolism, and burns more calories. Standing desks are a healthy means of increasing both physical activity and mental focus in the work place. Known standing desks typically are expensive, heavy-weight furniture pieces, utilize materials that are difficult if not impossible to recycle, and are not produced from sustainable materials and processes. 
         [0004]    Corrugated fiberboard (which we sometimes refer to simply as cardboard) has long been used in the shipping and transit industries. The material is recyclable, sustainable, and lightweight, and provides an inexpensive means to package items. Single wall cardboard typically has a fluted layer sandwiched between two kraft liner boards. Designers have used corrugated fiberboard for both home and office furniture. This furniture is lightweight, can be flat-packed when not assembled, is recyclable, and is readily customizable with pens or paints. 
         [0005]    Known single-wall cardboard desks have complicated assembly procedures leading to user frustration and also contain multiple parts resulting in expensive manufacturing costs. Known cardboard desk designs do not have the lateral or torsional stability to adequately support a higher standing work surface. Known cardboard desk designs utilize fasteners and glues to achieve stiffness and rigidity. 
       SUMMARY 
       [0006]    By folding corrugated cardboard sheets (in some cases single wall corrugated cardboard sheets) into simple rectangular and triangular prisms that easily slot together, an elegant cardboard standing desk can be achieved which is easy to assemble and affordable. This standing desk employs a new joint design which tightens as prisms are slotted into one another and becomes stiffer when the structure is heavily weighted. 
         [0007]    A piece of furniture such as a standing desk is constructed of intersecting folded prisms provided with a novel slot joint system. This novel slot joint affords greater lateral and torsional stability, simplicity, and long life to such furniture. Folding and mating such prisms using the slot joint system enables the construction of simple, durable, and lightweight structures which can be implemented as furniture having work surfaces of varying heights. 
         [0008]    A primary objective is to provide lightweight, flat-packing and inexpensive furniture solutions. 
         [0009]    Another objective is to provide a unique locking slot joint design with a folded conjoined structural prism design creating a construction system which allows for lightweight, simple, and rigid furniture pieces produced from flat material sheets such as corrugated cardboard. 
         [0010]    A further objective is to implement the construction system using sheets of corrugated cardboard (in many cases, single-wall corrugated cardboard) to produce standing desks or other table structures of varying heights that are affordable, flat-packing, lightweight, strong, easy to assemble, and eco-friendly. 
         [0011]    In some instances, the furniture unit comprises at least three flat corrugated sheets corresponding to a horizontal work surface A and two vertical support structures B, C. A fourth corrugated sheet D may be implemented as a support brace. ( FIG. 1 ) 
         [0012]    Thus, in general, in an aspect, a cardboard furniture structure includes at least two separate folded cardboard structural pieces, each of the two pieces including at least two conjoined prisms. A first one of the two pieces forms a vertical support. A second one of the two pieces includes a non-vertical functional surface. The two separate folded cardboard structural pieces are interconnected at one or more slot joints. The slot joints are configured to hold the two separate folded cardboard structural pieces together and to enhance the strength of the cardboard furniture structure. 
         [0013]    Implementations may include one or any combination of two or more of the following features. The cardboard furniture structure includes a third separate folded cardboard structural piece that includes at least two conjoined prisms and forms a second vertical support. The third piece and the first one of the two pieces interconnect with the second piece at one or more slot joints. The slot joints are configured to join the second piece with the first piece and the third piece to enhance the strength (and stiffness) of the cardboard furniture structure. There is also a fourth separate folded cardboard structural piece. The fourth piece is configured to connect to the first and third pieces at two or more slot joints. The slot joints are configured to enhance the strength (and stiffness) of the cardboard furniture structure. The non-vertical functional surface includes a desk surface. The cardboard furniture structure forms a desk. The cardboard furniture structure forms a standup desk. The cardboard furniture structure forms a desk that is configured to be placed on an existing desk to form a standup desk. The two conjoined prisms of the second piece include triangular prisms. The two conjoined prisms of the first piece include rectangular prisms. At least one of the pieces includes a folded sheet of single-wall cardboard. Each of the slot joints includes two slots, one on each of the pieces. Each of the two separate folded cardboard structural pieces includes panels formed by folding cardboard sheets, and the slot on each of the pieces includes at least two adjacent slot elements that are formed on respectively different panels of the folded cardboard sheets. At least one of the slots of one of the slot joints is tapered to enhance the strength of the cardboard furniture structure when the slot joint is formed. 
         [0014]    In general, in an aspect, a cardboard furniture structure is formed by folding at least two sheets of single-wall cardboard to form two folded cardboard structural pieces each including at least two conjoined prisms and at least two slot elements that cooperate to form a slot of the structural piece. One of the slots on one of the structural pieces is mated with a corresponding one of the slots on the other piece to form a slot joint that connects the two pieces and enhances the strength of the cardboard furniture structure. 
         [0015]    Implementations may include one or any combination of two or more of the following features. A third sheet of single-wall cardboard is folded to form a third cardboard structural piece that includes at least two conjoined prisms and at least two slot elements that cooperate to form a slot of the third structural piece. One of the slots of the third structural piece is mated with one of the two structural pieces to form a slot joint that connects the pieces and enhances the strength of the cardboard furniture structure. 
         [0016]    In general, in an aspect, a cardboard standup desk includes two folded single-wall cardboard vertical support pieces, each of the two vertical support pieces including two conjoined rectangular prisms and a slot formed of three slot elements on respective panels of the folded single-wall cardboard vertical support piece. A third folded single-wall cardboard work surface piece includes two conjoined triangular prisms and two slots each formed of two slot elements on respective panels of the folded single-wall cardboard work surface piece. The two slots of the work surface piece are mated with the two respective slots of the two vertical support pieces. A fourth folded single-wall cardboard non-vertical support piece connects the two vertical support pieces at a location below the work surface piece. 
         [0017]    These and other features, aspects, and implementations can be expressed as systems, components, apparatus, methods, means or steps for performing functions, and in other ways. 
         [0018]    These and other features, aspects, and implementations will become apparent from the following description, and from the claims. 
     
    
     
       DESCRIPTION 
         [0019]      FIG. 1  is an unfolded view of the parts of a disassembled standing desk. 
           [0020]      FIG. 2  is a front view of a fully assembled standing desk. 
           [0021]      FIG. 3  is a side view of a fully assembled standing desk. 
           [0022]      FIG. 4  is an isometric view of a partially assembled standing desk in which prism C is being inserted into prism A. 
           [0023]      FIG. 5  is a fully assembled isometric view of a standing desk. 
           [0024]      FIG. 6  is a shaded detail of an outer face of a locking joint that connects a standing desk vertical support to a work surface. 
           [0025]      FIG. 7  is a wireframe detail of an outer face of a locking joint that connects a standing desk vertical support to a work surface. 
           [0026]      FIG. 8  is a shaded detail of an inner face of a locking joint that connects a standing desk vertical support to a work surface. 
           [0027]      FIG. 9  is a wireframe detail of an inner face of a novel locking joint that connects a standing desk vertical support to a work surface. 
       
    
    
     DESK COMPONENTS 
       [0028]    A first rectangular sheet A includes six parallel scores  61 ,  62 ,  63 ,  64 ,  65 ,  66  and four parallel slots  1 ,  2 ,  3 ,  4 . The six parallel scores  61 ,  62 ,  63 ,  64 ,  65 ,  66  separate the sheet into seven horizontal panels  20 ,  21 ,  22 ,  23 ,  24 ,  25 ,  26 . Of the four parallel slots, two slots with thickness (or width) xx are cut on opposite sides of panels  21  and  22  perpendicular to the score  62 . Slots  1 ,  2  begin in the middle of panel  21  and terminate in panel  22 , just short of the score  63 . The remaining two slots with thickness (width) xx are cut on opposite sides of panels  24  and  25  perpendicular to the score  65 . Slots  3  and  4  begin near the  64  score and in panel  24  and terminate in the middle of panel  25 . ( FIG. 1 ) 
         [0029]    A second rectangular sheet B includes eight parallel scores  71 ,  72 ,  73 ,  74 ,  75 ,  76 ,  77 ,  78  three vertical support slots  5 ,  6 ,  7  of width xxxx and four horizontal brace slots  11 ,  12 ,  13 ,  14  of width x The eight parallel scores  71 ,  72 ,  73 ,  74 ,  75 ,  76 ,  77 ,  78  separate the sheet into nine vertical panels  31 ,  32 ,  33 ,  34 ,  35 ,  36 ,  37 ,  38 ,  39 . Each of the three vertical support slots  5 ,  6 ,  7  is tapered from a broad end at the edge of the panel to a narrow end that has width xxxx. The three vertical support slots  5 ,  6 ,  7  are parallel to all scores and lie along the top edge of sheet B. Slot  5  lies along score  71 , slot  6  is positioned in the middle of panel  35 , and slot  7  lies along score  78 . Four horizontal brace slots  11 ,  12 ,  13 ,  14  are perpendicular to scores in sheet B and are positioned near the bottom of sheet B. Slots  11 ,  12  are positioned along score  75  beginning in panel  35  and terminating near score  76  in panel  36 . Slots  13 ,  14  lie along the right edge of sheet B in panel  39  and are aligned with slots  11 ,  12  respectively. Slots  13 ,  14  merge into a broader opening along the edge of the sheet as shown. Sheet B may also contain four locking tabs  101 ,  102 ,  103 ,  104  and two other locking tabs  109 ,  110  to aid the assembly of the disclosed piece of furniture. ( FIG. 1 ). Each of the locking tabs is die cut into the sheet and can be folded out as a tab. 
         [0030]    A third rectangular sheet C, like sheet B, includes eight parallel scores  81 ,  82 ,  83 ,  84 ,  85 ,  86 ,  87 ,  88  three vertical support slots  8 ,  9 ,  10  of width xxxx and four horizontal brace slots  15 ,  16 ,  17 ,  18  of width x. The eight parallel scores  81 ,  82 ,  83 ,  84 ,  85 ,  86 ,  87 ,  88  separate the sheet into nine vertical panels  41 ,  42 ,  43 ,  44 ,  45 ,  46 ,  47 ,  48 ,  49 . Each of the three vertical support slots  8 ,  9 ,  10  is tapered from a broad end at the edge of the panel to a narrow end that has width xxxx. The three vertical support slots  8 ,  9 ,  10  are parallel to all scores and lie along the top edge of sheet C. Slot  8  lies along score  81 , slot  9  is positioned in the middle of panel  45 , and slot  10  lies along score  88 . Four horizontal brace slots  15 ,  16 ,  17 ,  18  are perpendicular to scores in sheet C and are positioned near the bottom of sheet C. Slots  15 ,  16  are positioned along score  84  beginning in panel  45  and terminating near score  83  in panel  44 . Slots  17 ,  18  lie along the left edge of sheet C in panel  41  and are aligned with slots  15 ,  16  respectively. Sheet C may also contain four locking tabs  105 ,  106 ,  107 ,  108  and two other locking tabs  111 , 112  to aid the assembly of the disclosed piece of furniture. ( FIG. 1 ). Each of the locking tabs is die cut into the sheet and can be folded out as a tab. 
         [0031]    A fourth sheet D may be used as a support brace for the piece of furniture and includes four parallel scores  91 ,  92 ,  93 ,  94  that separate five horizontal panels  51 ,  52 ,  53 ,  54 ,  55 . Sheet D may also contain two side panels  56 ,  57  to maintain the prism structure when folded. Sheet D has two pairs of parallel slots  113 ,  114  and  115 ,  116  all of width x that lie along the top edge of panel  53  and along the bottom edge of panel  55  respectively. ( FIG. 1 ) 
         [0032]    In some implementations of a desk design intended for working while standing, the panels and slots of sheet A have the following dimensions outlined in these tables. 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 Panel 
                 Width (inches) 
                 Height (inches) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 20 
                 41.5 
                 11.5 
               
               
                 21 
                 41.5 
                 9 
               
               
                 22 
                 41.5 
                 14.875 
               
               
                 23 
                 41.5 
                 24.25 
               
               
                 24 
                 41.5 
                 14.875 
               
               
                 25 
                 41.5 
                 9 
               
               
                 26 
                 41.5 
                 11.5 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
             
           
               
                   
               
               
                   
                 Distance 
                   
                 Short Slot 
                 Long Slot 
               
               
                   
                 to Edge 
                 Thickness [xx] 
                 Segment 
                 Segment 
               
               
                 Slot 
                 (inches) 
                 (inches) 
                 (inches) 
                 (inches) 
               
               
                   
               
             
             
               
                 1 
                 5.625 
                 0.375 
                 4.5 
                 14.1875 
               
               
                 2 
                 5.625 
                 0.375 
                 4.5 
                 14.1875 
               
               
                 3 
                 5.625 
                 0.375 
                 4.5 
                 14.1875 
               
               
                 4 
                 5.625 
                 0.375 
                 4.5 
                 14.1875 
               
               
                   
               
             
          
         
       
     
         [0033]    In such implementations, the panels and slots of sheet B may have the following dimensions outlined in these tables. 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 Panel 
                 Width (inches) 
                 Height (inches) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 31 
                 11.75 
                 41.5 
               
               
                 32 
                 5.8125 
                 41.5 
               
               
                 33 
                 12 
                 41.5 
               
               
                 34 
                 6.0 
                 41.5 
               
               
                 35 
                 24.0625 
                 41.5 
               
               
                 36 
                 6.0 
                 41.5 
               
               
                 37 
                 12 
                 41.5 
               
               
                 38 
                 5.8125 
                 41.5 
               
               
                 39 
                 11.75 
                 41.5 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
             
           
               
                   
               
               
                   
                   
                 Narrow End 
                   
               
               
                   
                 Broad End 
                 Thickness [xxxx] 
               
               
                 Slot 
                 Thickness (inches) 
                 (inches) 
                 Length (inches) 
               
               
                   
               
             
             
               
                 5 
                 0.98 
                 0.52 
                 4.7513 
               
               
                 6 
                 0.98 
                 0.52 
                 4.7513 
               
               
                 7 
                 0.98 
                 0.52 
                 4.7513 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
               
               
                   
                 Distance 
                   
                 Short Slot 
                 Long Slot 
               
               
                   
                 to Bottom 
                 Thickness [x] 
                 Segment 
                 Segment 
               
               
                 Slot 
                 Edge (inches) 
                 (inches) 
                 (inches) 
                 (inches) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 11 
                 13.875 
                 0.1875 
                 3 
                 4.375 
               
               
                 12 
                 9.9 
                 0.1875 
                 3 
                 4.375 
               
               
                 13 
                 13.875 
                 0.1875 
                 2.8941 
                 — 
               
               
                 14 
                 9.9 
                 0.1875 
                 2.8941 
                 — 
               
               
                   
               
             
          
         
       
     
         [0034]    In such implementations, the panels and slots of sheet C have the following dimensions outlined in these tables. 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 Panel 
                 Width (inches) 
                 Height (inches) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 41 
                 11.75 
                 41.5 
               
               
                 42 
                 5.8125 
                 41.5 
               
               
                 43 
                 12 
                 41.5 
               
               
                 44 
                 6.0 
                 41.5 
               
               
                 45 
                 24.0625 
                 41.5 
               
               
                 46 
                 6.0 
                 41.5 
               
               
                 47 
                 12 
                 41.5 
               
               
                 48 
                 5.8125 
                 41.5 
               
               
                 49 
                 11.75 
                 41.5 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
                 Broad End 
                   
                   
               
               
                   
                   
                 Thickness 
                 Narrow End Thickness 
                 Length 
               
               
                   
                 Slot 
                 (inches) 
                 [xxxx] (inches) 
                 (inches) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 8 
                 0.98 
                 0.52 
                 4.7513 
               
               
                   
                 9 
                 0.98 
                 0.52 
                 4.7513 
               
               
                   
                 10 
                 0.98 
                 0.52 
                 4.7513 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
               
               
                   
                 Distance 
                   
                 Short Slot 
                 Long Slot 
               
               
                   
                 to Bottom 
                 Thickness [x] 
                 Segment 
                 Segment 
               
               
                 Slot 
                 Edge (inches) 
                 (inches) 
                 (inches) 
                 (inches) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 15 
                 13.875 
                 0.1875 
                 3 
                 4.375 
               
               
                 16 
                 9.9 
                 0.1875 
                 3 
                 4.375 
               
               
                 17 
                 13.875 
                 0.1875 
                 2.8941 
                 — 
               
               
                 18 
                 9.9 
                 0.1875 
                 2.8941 
                 — 
               
               
                   
               
             
          
         
       
     
         [0035]    In such implementations, the panels and slots of sheet D have the following dimensions outlined in these tables. 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 Panel 
                 Width (inches) 
                 Height (inches) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 51 
                 30.5 
                 5.75 
               
               
                 52 
                 30.125 
                 3.8125 
               
               
                 53 
                 39.25 
                 6 
               
               
                 54 
                 39.25 
                 4 
               
               
                 55 
                 39.25 
                 6 
               
               
                 56 
                 4.5625 
                 3.4375 
               
               
                 57 
                 4.5625 
                 3.4375 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
                 Thickness [x] 
                   
                 Distance to Edge 
               
               
                   
                 Slot 
                 (inches) 
                 Length (inches) 
                 (inches) 
               
               
                   
                   
               
             
             
               
                   
                 113 
                 0.1875 
                 3 
                 4 
               
               
                   
                 114 
                 0.1875 
                 3 
                 4 
               
               
                   
                 115 
                 0.1875 
                 3 
                 4 
               
               
                   
                 116 
                 0.1875 
                 3 
                 4 
               
               
                   
                   
               
             
          
         
       
     
         [0036]    A wide variety of other examples fall within the concepts that we are discussing here. Among other things, the slots should have dimensions and configurations such that when the pieces of the item of furniture are assembled, the slotted joints formed by the slots and the portions of cardboard with which they interact achieve stability and strength in the ways that we have described. 
       Desk Folding 
       [0037]    To assemble the furniture piece, sheets A, B, C, D are folded into separate elongated prism structures. ( FIG. 1 ,  FIG. 4 ) 
         [0038]    Sheet A is folded into two conjoined right triangle prisms by first mating the rear side of panel  20  with the front side of panel  23  and then mating the rear side of panel  26  with the front side of panel  23  such that rear sides of panels  21 ,  25  also mate with one another. When sheet A is folded, slots  1 ,  3  align and slots  2 ,  4  align to create compound slots here referred to as slots A 1 , A 2  respectively. Sheet A in its folded state, which includes the two conjoined prisms, is referred to as prism A. ( FIG. 1 ,  FIG. 4 ,  FIG. 6 ) 
         [0039]    Sheet B is folded into two conjoined rectangular prisms by first mating the rear side of panel  31  with the front side of panel  35  and then mating the rear side of panel  39  with the front side of panel  35  such that the rear side of panels  32 ,  38  also mate with one another. Since quadruple slots  5 ,  7  are subdivided by scores  71 ,  78  respectively, when folded and positioned adjacently they add together to form a quadruple slot which aligns with quadruple slot  6 . When sheet B is folded slots  5 ,  6 ,  7  align to create a compound slot here referred to as compound slot B 1 . Slots  11 ,  12  align with slots  13 ,  14  respectively to create compound slots here referred to as compound slots B 2 , B 3  respectively. Sheet B in its folded state, which includes the two conjoined prisms, is here referred to as prism B. ( FIG. 1 ,  FIG. 4 ,  FIG. 6 ) 
         [0040]    Sheet C, like sheet B, is folded into two conjoined rectangular prisms by first mating the rear side of panel  41  with the front side of panel  45  and then mating the rear side of panel  49  with the front side of panel  45  such that the rear side of panels  42 ,  48  also mate with one another. Since quadruple slots  8 ,  10  are subdivided by scores  81 ,  88  respectively, when folded and positioned adjacently they add together to form quadruple slot which aligns with quadruple slot  9 . When sheet C is folded slots  8 ,  9 ,  10  align to create a compound slot here referred to compound slot C 1 . Slots  15 ,  16  align with slots  17 ,  18  respectively to create compound slots here referred to as compound slots C 2 , C 3  respectively. Sheet C in its folded state, which includes the two conjoined prisms, is here referred to as prism C. ( FIG. 1 ,  FIG. 4 ) 
         [0041]    Sheet D is folded into a simple rectangular prism by mating the rear side of panel  51  with the front side of panel  55 . Panels  56  are folded such that they lie perpendicular to planes created by panels  51 ,  52 ,  53 ,  54 ,  55  and cap the ends of the rectangular prism. Sheet D in its folded state is here referred to as prism D. ( FIG. 1 ,  FIG. 4 ) 
       Desk Assembly 
       [0042]    Assembly of the furniture piece is achieved by firstly interlocking prism A and prism B such that compound slot A 2  mates with compound tapered slot B  1 . ( FIG. 6 ,  FIG. 7 ,  FIG. 8 ,  FIG. 9 ).  FIGS. 6-9  display a truncated portion of prism B to illustrate its internal folding structure which creates a t-shaped slot-mate structure. This mate is achieved by inserting prism B&#39;s coincident panels  31 ,  35 ,  39  into compound slot A 2  and simultaneously inserting prism B&#39;s coincident panels  32 ,  38  such that they wedge between prism A&#39;s right coincident panels  21 ,  25  of its two right triangular prisms. ( FIG. 7 ,  FIG. 9 ) 
         [0043]    Assembly is continued by next interlocking prism A and prism C in a similar way, such that compound slot A 1  mates with compound tapered slot C 1 . This mate is achieved by inserting prism C&#39;s coincident panels  41 ,  45 ,  49  into compound slot A 1  and simultaneously inserting prism C&#39;s coincident panels  42 ,  48  such that they wedge between prism A&#39;s right coincident panels  21 ,  25  of its two right triangular prisms. ( FIG. 1 ) 
         [0044]    More simply, when viewed from above Prism A (the work surface) has two T-shaped female channels that receive the T-shaped male plugs created by the adjacent rectangular prisms in Prism B and C (the vertical support structures). ( FIG. 4 ,  FIG. 6 ,  FIG. 8 ). This unique slot mate design stiffens as prisms B, C are inserted into prism A. Tapered compound slots B 1 , C 1  clamp together the work surface&#39;s adjacent triangular prisms while the inner bisecting panels of the two vertical support structures wedge apart the work surface&#39;s triangular prisms. ( FIG. 7 ,  FIG. 9 ). By simultaneously separating and compressing the adjacent triangular prisms of the work surface, the joints achieve both strength and stiffness. This novel joint design provides stability while minimizing weight and complexity of the disclosed furniture piece. ( FIG. 2 ,  FIG. 3 ,  FIG. 5 ) 
         [0045]    A support brace may be added to the furniture piece to provide further lateral stability for the structure by interlocking prism D with prisms B, C. This mate is achieved by inserting slots  113  and  115  into compound slots B 2  and B 3  respectively and simultaneously inserting slots  114  and  116  into compound slots C 2  and C 3  respectively. The mate is configured such that panel  54  on prism D lies flush with panels  36  on prism B and  44  on prism C. The mate is also configured such that panels  56 ,  57  on prism D lie flush with panel  35  on prism B and panel  45  on prism C respectively. Support brace prism D wedges apart vertical support prisms B and C to increase stiffness and lateral stability of the disclosed furniture piece. This is achieved because the horizontal distance between slot pair  113 , 115  and slot pair  114 , 116  in prism D is slightly greater than the slot distances between compound slots A 1  and A 2  in prism A. 
       Other Embodiments of the Desk 
       [0046]    A wide variety of other embodiments of desks and other pieces of furniture can make use of the principles that we describe here. For example, in some embodiments of a furniture piece, the heights of vertical support prisms B, C can be shortened or increased to cater to a wider range of user heights. In some implementations, the heights of the vertical support prisms B, C can be radically shortened and prism D and corresponding compound slots B 2 , B 3  in prism B and compound slots C 2 , C 3  in prism C can be eliminated such that the furniture piece can be placed upon a the surface of a sedentary desk to transform it into a standing desk. In some implementations, prisms B, C can be designed so that prism A rests on an incline to achieve an inclined standing work surface. 
         [0047]    Other implementations are also within the scope of the following claims. 
         [0048]    For example, although we sometimes refer to the cardboard as being single-wall, it is also possible to use other categories of cardboard.