# create 'dragbug' with a pure tkinter program


# DRAG AROUND THE RED SQUARE AS FAST AS POSSIBLE
# AND THE PROGRAM WILL CRASH AFTER A VIEW SECONDS,
# DISPLAYING:

"""Runtime ERror!

Program C:\Python31\pythonw.exe

This application has requested the Runtime to terminate it in an unsusual way.
Please contakt the application's support team for more information.
"""
# IF STARTED FROM WITHIN IDLE,  IDLE CLOSES IMMEDIATELY
# IF STARTED FROM A COMMAND_LINE (UNDER WINDOWS):
""" Fatal Python error: Cannot recover from stack overflow.
"""

REPETITIONS = 5      # The larger REPETITIONS, the earlier occurs the crash

from tkinter import *

root = Tk()
cv = Canvas(width=800, height=800, background="white")
cv.pack()

r = cv.create_rectangle(390, 390, 410, 410, fill="red")
l = cv.create_line(400, 400, 400, 400, fill="blue")

def move(event):
    x, y = event.x, event.y
##    print(x,y)
    cv.coords(r, x-10, y-10, x+10, y+10)
    cl = list(cv.coords(l))
    for i in range(REPETITIONS):
        cl.extend([x, y])
        cv.coords(l, *cl)
        cv.update()

cv.tag_bind(r, "<Button1-Motion>", move)
root.mainloop()