anchor.diff:  
   	    (setf (aref pix-a-volta ipix) a-volta)
   	    (push ipix pix-natribuidos)
  -	    
  +
   	    (when (numberp pix)
   	      (when (> pix a-volta-len) (setf pix-solucionavel nil) (return-from ciclos))
   
  +	      (setf (aref pix-pix ipix) pix)
   	      (let* ((restricao (cria-restricao-fapix a-volta pix a-volta-len))
   		     (dominio (if (= pix 0) (list 0) (if (= pix a-volta-len) (list 1) nil))))
   
  
positive.code:     (when (fapix-completo-p f)
        (return-from procura-retrocesso-fc-mrv-fapix (values f testes-totais)))
  
      (let* ((ipix (fapix-mrv f))
  	   (d (fapix-pix-dominio f ipix))
  	   )
  ;      (format t "Vou experimentar a variavel:~a cujo dominio e:~a~%" ipix (fapix-pix-dominio f ipix))
        ; TODO: heuristica de valor (media dos pixs a volta? implica mais um array)
        (dolist (cor d)
  	(multiple-value-bind (consistente testes) (fapix-atribuicao-consistente-p f ipix cor)
  	  (incf testes-totais testes)
  
negative.code: 		:relacionados pix-relacionados
  		:natribuidos pix-natribuidos
  		:solucionavel pix-solucionavel
  		:dominio-len dominio-len
  		:pix pix-pix
  		:hv pix-hv)))
  
  (defun fapix->fill-a-pix (f)
    ""
  