from tkinter import *
from random import *

master = Tk()
width, height = 400,400
w = Canvas(master, height=height, width=width)
w.pack()

def zz(max):
    return randint(1,max)

def farbe():
    r=zz(255)
    g=zz(255)
    b=zz(255)
    return "#%02x%02x%02x" % (r,g,b)

class Linie(object):

    def __init__(self):
        self.xs = zz(width)
        self.ys = zz(height)
        self.x = zz(width)
        self.y = zz(height)
        self.farbe = "yellow"
        w.create_line(self.xs,self.ys,self.x,self.y,fill=self.farbe)

        
    def verlaengern(self):
        self.xs=self.x
        self.ys=self.y
        self.x = zz(width)
        self.y = zz(height)
        self.farbe=farbe()
        w.create_line(self.xs,self.ys,self.x,self.y,fill=self.farbe)
        w.after(100, self.verlaengern)


linie = Linie()
linie.verlaengern()

w.mainloop()