plotting slows down

[norman.elliott at gmail.com]

First let me say I have not done much python programming!
I am running Python 2.7.3.
I am trying to use python as a front end to a simple oscilloscope.
Ultimately I intend to use it with my micropython board.

At the moment I am just developing it. All it does is use a module I found called graphics.py to create a window and display randomly generated data.

Each time it goes through the outer loop it gets slower and slower.
I put in a small delay just so I could observe what is happening and for the first line it draws it takes about a second. If I set it to loop 20 times the final loop takes more than 6 seconds.
Can anyone explain what I am doing wrong please?
Here is the code:
[code]
#!/usr/bin/python
from graphics import *
import random
import time

xpos=1200
ypos=400
ypnt=ypos/2
pos=1
#setBackground("white")
def main():
	win = GraphWin("My Circle", xpos, ypos)
#	win.setBackGround('white')
	for y in range(1,5):
		cir2 = Circle(Point(xpos/2,20), 10)
		cir2.setFill("white")
		cir2.draw(win)
		message = Text(Point(win.getWidth()/2, 20), y)
		message.draw(win)
		j = random.randint(1,ypos)
		for x in range(1,xpos):
			updown = random.randint(0,1)
			if updown:
				j=j+1
			else:
				j=j-1
			if j <1:
				j=ypos/2
			if j>ypos-1:
				j=ypos/2
			win.plot(x,j,"red")
			time.sleep(.0001)

main()
time.sleep(5)
[/code]