anchor.diff:                       (cloud-chunk-among-chunks cloud (visible-chunks rbm)))
                       (hidden-chunk
                        (cloud-chunk-among-chunks cloud (hidden-chunks rbm))))
  -                (maybe-add-connection
  -                 cloud
  -                 :from (ensure-lumpy (1+ depth) visible-chunk)
  -                 :to (ensure-lumpy depth hidden-chunk))
  +                (unless (typep hidden-chunk 'conditioning-chunk)
  +                  (add-connection cloud
  +                                  :from (ensure-lumpy (1+ depth) visible-chunk)
  +                                  :to (ensure-lumpy depth hidden-chunk)))
                   (unless (or (typep visible-chunk 'conditioning-chunk)
                               bottom-up-only)
                     ;; If the chunk does not need activations then it is
  
positive.code:                   ;; :RECONSTRUCTION lumpies (higher -> lower).
                    (when (and (or (member higher-chunk reconstruction)
                                   (zerop higher-depth))
                               (member lower-chunk reconstruction))
                      (maybe-add-connection
                       cloud
                       :from (ensure-lumpy (- higher-depth) higher-chunk
                                           (if (zerop higher-depth)
  
negative.code:                          (if (typep hidden-chunk 'conditioning-chunk)
                               depth
                               (- depth))))
                      (add-connection cloud
                                      :from (ensure-lumpy hidden-depth
                                                          hidden-chunk)
                                      :to (ensure-lumpy (- (1+ depth))
                                                        visible-chunk)))))))
        (lumpies->bpn-definition lumpies))))
  
  (defun unroll-dbm (dbm &key (chunks (chunks dbm)) (map chunks)
  