#!/usr/bin/python
# -*- coding: utf-8 -*-

from tkinter import *
import time
from random import * 

window = Tk()
sizex = 400
sizey = 600
canvas = Canvas(window, width = sizex, height = sizey)
canvas.pack()
x = 100		# initial left-most edge of first ball
y = 30		# initial top-most edge of first ball
r = 16                  # ball diameter 
depx = 2            # displacement at each move in x direction
depy = 0            # displacement at each move in y direction

# create balls:
no_particles = 20
dy = (sizey-2.*y)/(no_particles+1)       # y initial separation between balls
print(dy)
ball_list = []
for i in range(no_particles):
    ball = canvas.create_oval(x,y,x+r,y+r,fill="blue")
    y = y+dy
    ball_list.append(ball)

#moves
no_moves = 100
for j in range(no_moves):
    for ball in ball_list:
        canvas.move(ball, depx, choice([-2, 2]) )
#        canvas.move(ball, depx, depy)
    canvas.after(10)
    canvas.update()

time.sleep(5) # on attend quelques secondes
window.destroy()