pg 9






	 r.1 --------+


 

                       |  |                |
                       |  +-- and --- S ---+
		       |  |   |       |    |
		       |  |   |       |    |
 		       +--|---+       |    |
		       |  |           |    |
		    +-----|-----------+    | 
                    |  |  |                |
                    |  |  |                |
                    |  |  |                |
                    |  |  +-- or ---- S ---+
		    |  |  |   |       |    |
		    |  |  |   |       |    |
 		    |  +--|---+       |    |
		    |  |  |           |    |
		   +------|-----------+    | 
                       |  |                |
                       |  |                |
                       |  +-- xor --- S ---+
		       |  |   |       |    |
		       |  |   |       |    |
 		       +--|---+       |    |
		       |  |           |    |
		  +-------|-----------+    | 
                       |  |                |
                       |  |                |
                       |  +-- not --- S ---+
		       |  |           |    |
		       |  |           |    |
 		       |  |           |    |
		       |  |           |    |
		 +--------|-----------+    | 
                       |  |                |
                       |  |                |





		     | 
                     +-- or --- S ----
		     |   |      |
		     |   |      |
		  ---|---+
		     | 





	r.2