You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    The present invention claims priority to U.S. Provisional Patent Application Serial No. 60/448,506 filed on Feb. 19, 2003 and entitled “Wall Panel For A Portable Restroom.” 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention generally relates to a portable restroom. More specifically, to a wall panel for a portable restroom and a method of making such a wall panel for a portable restroom.  
         BACKGROUND  
         [0003]    Portable restrooms are in wide-spread use today at construction sites, campgrounds, outdoor entertainment events and the like. Such portable restrooms typically have a roof connected to three side panels and a front panel having a door. The side panels and door panel are connected to a base. Prior art restrooms have wall panels that have exterior surfaces having styling lines and other features for improving the aesthetic appearance and structural integrity of the wall panel. While prior art portable restrooms incorporate wall panels that achieve their intended purpose, many problems still exist. For example, the styling lines and other features incorporated into the exterior surface of the wall panels create an interior surface of the wall panel that is replete with indentations and other features which creates a non-smooth interior surface on each of the wall panels. This non-smooth surface makes it more difficult to clean the interior surfaces of the restroom.  
           [0004]    Therefore, what is needed is a new system and method for manufacturing the wall panels of a portable restroom. The new and improved system and method should allow the portable restroom interior to be cleaned more easily. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    Further features and advantages of the invention will become apparent from the following discussion and the accompanying drawings in which:  
         [0006]    [0006]FIG. 1 is perspective view of the portable restroom incorporating the wall and door panels of an embodiment of the present invention;  
         [0007]    [0007]FIG. 2 is a front view of the outside surface of the wall panel of the portable restroom of FIG. 1, in accordance with an embodiment of the present invention;  
         [0008]    [0008]FIG. 3 is a cross-sectional view of the wall panel of FIG. 2 along lines A-A;  
         [0009]    [0009]FIG. 4 is a front view of the inside surface of the wall panel of the portable restroom of FIG. 1; and  
         [0010]    [0010]FIG. 5 is a flow chart illustrating a method for manufacturing a wall panel, in accordance with an embodiment of the present invention.  
     
    
     BRIEF SUMMARY OF THE INVENTION  
       [0011]    In an aspect of the present invention, a portable restroom having a wall panel is disclosed. The wall panel of the present invention has an outside surface and an inside surface. The inside surface of the wall panel is smooth with out any indentations or recesses. The exterior surface of the wall panel, generally, has impressions formed therein.  
         [0012]    In yet another aspect of the present invention, a method of making a wall panel having a smooth interior surface is disclosed.  
       DESCRIPTION  
       [0013]    The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention or its application or uses.  
         [0014]    Referring in particular to FIGS. 1 and 2, a portable restroom for use in public is generally shown and represented by reference numeral  10 . As shown in FIG. 1, the portable restroom  10  has wall panels  12 ,  14  and  15  that form the sides and back of the restroom. The portable restroom  10  also includes a door panel  17  having a door as shown in phantom. It should be understood that wall panels  12 ,  14  and  15  shown in phantom are substantially identical.  
         [0015]    Portable restroom  10  also includes a roof  16  and a base  18 . As shown in FIG. 1, roof  16  and base  18  are positioned on top and bottom respectively, of wall panels  12 ,  14 , and  15 . The wall panels  12 ,  14  and  15 , roof  16  and base  18  form an enclosure  20 . Enclosure  20  includes a tank  22  having an aperture covered by a toilet seat  24  and a vent pipe  26  for venting gases accumulating in tank  22  out to atmosphere. The enclosure  20  also includes a toilet paper holder  28  attached to side panel  12 .  
         [0016]    Referring in particular to FIGS. 2, 3 and  4 , wall panels  12 ,  14  and  15  include an exterior surface  30  (shown in FIGS. 2 and 3) and an interior surface  32  (shown in FIGS. 3 and 4). As shown in FIG. 2, exterior surface  30  of wall panels  12 , 14  and  15  have knits or reinforcement ribs  34  to strengthen the panels (as shown in FIG. 3). The knit  34  are formed in pre-determined positions along the panel  12  such that exterior surface  30  is in contact with the interior surface  32 . Additionally, exterior surface  30  also includes style lines  36  that vary in length, and depth. These style lines  36  are indentations or raised sections on exterior surface  30  of the wall panels  12 .  
         [0017]    In order to facilitate the cleaning of interior surface  32  of side panels  12 ,  14 , and  15  interior surface  30  is smooth and does not have any reinforcement ribs or indentations or the like.  
         [0018]    In an embodiment of the present invention, a method  50  of forming wall panels  12 ,  14 , and  15  wherein exterior surface  30  is provided with knits  34  and style lines  36  and interior surface  32  is smooth is illustrated in FIG. 5. In order to form exterior surface  30  of wall panels  12 ,  14 , and  15  heat is applied to a first polymer sheet such as a plastic sheet, as represented by block  52 . The first polymer sheet is further heated to a first predefined temperature, as represented by block  54 . After the first polymer sheet has been heated to the first predefined temperature, a first mold having suitable inserts to form the reinforcement ribs and styling lines are pressed into contact with the first surface of the first sheet, as represented by block  56 . At block  58 , a vacuum is applied to the mold and first sheet, which draws the first sheet into the mold and transfers the impression in the mold to the surface of the first sheet.  
         [0019]    The interior surface  32  of wall panels  12 ,  14  and  15  are formed by heating a second polymer sheet, as represented by block  60 . The second polymer sheet is heated to a second predefined temperature, as represented by block  62 . The second sheet is pressed into contact with a second mold, as represented by step  64 . The second mold has no inserts. The second sheet is formed to the desired shape by applying vacuum to the mold and second polymer sheet, as represented by step  66 . In order to form wall panels  12 ,  14  and  15 , the first and the second molds are pushed together such that the first sheet having a first shape is knitted or joined to the second sheet with the second shape at pre-determined locations, as represented by block  68 . Thus, the wall panels  12 ,  14  and  15  are formed of two sheets of plastic that are knitted together at predefined locations.  
         [0020]    The above method  50  allows the side panels  12  or back panels to be formed, wherein the exterior surface has reinforcing ribs and styling lines and the interior surface is smooth. Additionally, in an embodiment of the present invention, the knits and reinforcing ribs are only formed and visible on the outside surface of the side or back wall panels of the restroom.  
         [0021]    As any person skilled in the art will recognize from the previous description and from the figures and claims, modifications and changes can be made to the preferred embodiment of the invention without departing from the scope of the invention as defined in the following claims.

Summary:
The present invention is generally directed towards a portable restroom and more specifically towards a wall panel for a portable restroom. The wall panel of the restroom has an exterior surface and an interior surface that are formed by thermoforming two plastic sheets. The exterior surface of the wall panel is formed having knit and decorative styling lines. The interior surface is smooth and free of any indentations or impressions.