anchor.diff:    (multiple-value-bind
           (units frac) (floor (- value inf) (* unit num-content-ticks))
       ;; (when *dbg*
  -    ;;   (format t "~&value:~A -> {units: ~A, frac: ~A}"
  +    ;;   (format *debug-io* "~&value:~A -> {units: ~A, frac: ~A}"
       ;;           value units frac))
       (with-output-to-string (s)
         (let ((most-tick (svref *vticks* num-content-ticks)))
  
positive.code:   * <size>     ~ maximum number of output columns (contains label).
    * <labels>   ~ labels for data.
    * <title>    ~ If title is too big for size, then not print.
    * <scale?>   ~ If strings of inf and sup is too big for size, then not print.
    * <newline?> ~ If T, output with newlines for easy to see.
  
  
  Examples:
  
negative.code:       (when (zerop unit) (setf unit 1))
  
        ;; (when *dbg*
        ;;   (format *debug-io* "~&sup: ~S~&inf: ~S~&unit: ~S~
        ;;                       ~%num-content-ticks: ~S~%size: ~S~%"
        ;;           sup inf unit num-content-ticks size))
  
        (loop
  