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

(defun scale (end step &optional current)
  (let ((curr (or current 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 1 0 0 M-x scale-simple RET        0.........10........20........30 ...

(provide 'scale)