anchor.diff:  
   (defun procura-retrocesso-simples (psr)
     (cond ((notany #'zerop psr)
  -     (if (psr-consistente-p psr)
  +     (if (psr-atribuicoes psr)
            psr
            nil))
  -    (t (let ((positions (fill-a-pix->psr psr)))
  -         (loop for position in positions
  -          do (loop for number in '(1 2 3 4 5 6 7 8 9)
  +    (t (let ((vars (PSR-listvalues psr)))
  +         (loop for var in vars
  +          do (loop for val in '(1 2 3 4 5 6 7 8 9)
                 do (let ((result (procura-retrocesso-simples
  -                        (psr->fill-a-pix psr
  -                            lin
  -                            col))))
  +                        (psr-atribuicao-consistente-p
  +                            psr
  +                            var
  +                            val))))
                      (when result
  -                 (return-from procura-retrocesso-simples result)))))))))+                    (return-from procura-retrocesso-simples result)
  +                   )
  +                 )
  +             )
  +         )
  +       )
  +    )
  +  )
  +)
  
positive.code: ; 70916
  
  ;;(compile-file "exemplos.lisp")    
  (load "exemplos.fas")       
  
  
  
  
negative.code: 				(setf listadevars (append listadevars (list (write-to-string cont))))
  				
  				(if (not (equal NIL (aref arr i j) ))
  				    (setf listaderestr
  				          (append listaderestr
  				                    (list (cria-restricao (GetNeighboursOfArrayCell aux i j)
  				                                          (CriaPredicado aux i j)
                                            )
                                      )
                            )
                      )
  				)
  				(incf cont)
  			)
  