# Tk_pattern_of_4.py

# Tk_pattern_of_4.py

import random
import time

try:
    from Tkinter import *
except:
    from tkinter import *

root=Tk()
root.title("Tk_pattern_of_4")

ww=640
hh=640

canvas = Canvas(root, width=ww,height=hh)
canvas.pack()

bricks = (
(0,0,40,20),
(0,20,40,40),
(0,0,20,40),
(20,0,40,40))

while 1:
    wait = time.time()+1
    canvas.delete('all')
    for x in range (0,ww,40):
        for y in range(0,hh,40):
            a,b,c,d = random.choice(bricks)
            brick = a+x,b+y,c+x,d+y
            canvas.create_rectangle(brick,fill='green',outline='green')
    canvas.update()
    while wait > time.time(): 0