(let ((left 0))
  (while t
    (switch-to-buffer (get-buffer-create "sample"))
    (let ((frame (make-frame `((parent-frame . ,(selected-frame))
                               (left . ,left)
                               (top . 1)
                               (width . 40)
                               (height . 3))))
          (buf (get-buffer-create "buffer-in-frame")))
      (setq left (1+ left))
      (with-selected-frame frame
        (switch-to-buffer buf)
        (insert "Hello!"))
      (redisplay))))