anchor.diff:      (make-instance
        'std-140
        :name name
  +     :type type
        :base-offset base-offset
        :aligned-offset (calc-aligned-offset base-offset n)
        :base-alignment n
  
positive.code:   ((name :initarg :name
           :initform nil
           :reader layout-name)
     (base-offset :initarg :base-offset
                  :initform nil
                  :reader layout-base-offset)
  
negative.code:     (make-instance
       'std-140
       :name name
       :type type
       :base-offset base-offset
       :base-alignment base-alignment
       :aligned-offset (calc-aligned-offset base-offset base-alignment)
  