anchor.diff:                    ;; :RECONSTRUCTION lumpies (higher -> lower).
                     (when (and (or (member higher-chunk reconstruction)
                                    (zerop higher-depth))
  -                             (member lower-chunk reconstruction))
  -                    (maybe-add-connection
  +                             (member lower-chunk reconstruction)
  +                             (not (typep lower-chunk 'conditioning-chunk)))
  +                    (add-connection
                        cloud
                        :from (ensure-lumpy (- higher-depth) higher-chunk
                                            (if (zerop higher-depth)
  
positive.code:                      (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 (or (typep visible-chunk 'conditioning-chunk)
                              bottom-up-only)
                    ;; If the chunk does not need activations then it is
  
negative.code:                  (push-all chunk-inits inits))))))
      (values (reverse defs) inits)))
  
  (defun add-connection (cloud &key from to)
    (assert (> (lumpy-depth from) (lumpy-depth to)))
    (assert (not (member from (lumpy-incomings to)
                         :key #'incoming-from-lumpy)))
    (assert (not (typep (chunk to) 'conditioning-chunk)))
    (push (make-incoming :from-lumpy from
                         :cloud cloud
                         :transposep (eq (lumpy-chunk from)
                                         (chunk2 cloud)))
          (lumpy-incomings to)))
  
  (defun ensure-lumpy (lumpies &key depth chunk kind)
    (or (find-lumpy lumpies :depth depth :chunk chunk :kind kind)
  