;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/scale.el

(defun scale (end step &optional curr)
  (or curr (setq curr 0))
  (when (<= curr end)
    (let*((digit-str     (if (zerop (% curr step))
                             (format "%s" curr)
                           ".") )
          (digit-str-len (length digit-str)) )
      (insert digit-str)
      (scale end step (+ digit-str-len curr)) )))

(defun scale-simple (&optional end)
  (interactive "P")
  (let*((e    (or (and (listp end) (car end))
                  (and (numberp end) end)
                  30) )
        (step (max 1 (/ e 10))) )
    (scale e step) ))

;; C-u     M-x scale-simple RET 01234
;; C-u C-u M-x scale-simple RET 012345678910121416
;;         M-x scale-simple RET 0..3..6..9..12.15.18.21.24.27.30
;; C-u 100 M-x scale-simple RET 0.........10........20........30 [...]

(provide 'scale)