#!/usr/bin/env python3

import tkinter
import time

Hauptfenster=tkinter.Tk()
Hauptfenster.geometry("600x400")

zettel = tkinter.Text(Hauptfenster, bg="white", width=50, height=20, font="Arial 10")
zettel.pack()

for i in range(1,30):
   zettel.insert("end",i)
   zettel.insert("end",". Textzeile.\n")
   time.sleep(1)

Hauptfenster.mainloop()