This picture shows that class objects like other objects---they're
instances of classes.  The class pointer in a class object points
to a class object that describes classes, called a metaclass.
In our system, we only have one metaclass object, called
<<class>>.  The class <<class>> describes itself as well
as other class objects, which is why its class pointer points
to itself.


   METACLASS OBJECT:                 NORMAL CLASS OBJECTS:
   (i.e., class <<class>>) 
                             
                                           +-------+          
       +-----------------------------------+---*   |         
       |                                   +=======+        
       |                             super |   *   |
       |                                   +-------+             
       |                              name |   *---+--> <object> 
       |                                   +-------+
       |                             slots |   *   |
       |                                   +-------+_
       |                                           |\
       |                                             \
       |  +-------+                                   |
       |  |       |                                   |
       v  v       |                                   |                          
      +-------+   |                                   | 
      |   *---+---+                        +-------+  | 
      +=======+ <--------------------------+---*   |  |
super |   *   |                            +=======+  | 
      +-------+                      super |   +---+--+           
 name |   *---+--> <<class>>               +-------+         
      +-------+                       name |   *---+--> <point>
slots |   *---+-> (super name slots)       +-------+    
      +-------+                      slots |   *---+--> (x y)
          ^                                +-------+_
          |                                        |\
          |                                          \         
          |                                           |
          |                                           |
          |                                           |  
          |                                +-------+  |
          +--------------------------------+---*   |  |                     
                                           +=======+  | 
                                     super |   *---+--+ 
                                           +-------+                       
                                      name |   *---+--> <colored-point>
                                           +-------+                
                                     slots |   *---+--> (x y color)
                                           +-------+