Przecinanie odcinków

from tkinter import *
import random

def Pole(xA, yA, xB, yB, xC, yC):
    s1 = xA*yB - yA*xB
    s2 = xB*yC - yB*xC
    s3 = xC*yA - yC*xA
    return (s1+s2+s3)/2

def Losuj():
    print("--- Losuj ----------------------------------------------")
    plotno.delete('all')
    plotno.create_window(10, 10, anchor=NW, window=przycisk)
    x1 = random.randrange(0, width)
    y1 = random.randrange(0, height)
    x2 = random.randrange(0, width)
    y2 = random.randrange(0, height)
    x3 = random.randrange(0, width)
    y3 = random.randrange(0, height)
    x4 = random.randrange(0, width)
    y4 = random.randrange(0, height)
    print("P1 : x =",x1,"y =",y1)
    print("P2 : x =",x2,"y =",y2)
    print("P3 : x =",x3,"y =",y3)
    print("P4 : x =",x4,"y =",y4)
    p1 = Pole(x3, y3, x4, y4, x1, y1)
    p2 = Pole(x3, y3, x4, y4, x2, y2)
    p3 = Pole(x1, y1, x2, y2, x3, y3)
    p4 = Pole(x1, y1, x2, y2, x4, y4)
    print("Pole 1 =",p1)
    print("Pole 2 =",p2)
    print("Pole 3 =",p3)
    print("Pole 4 =",p4)
    if ((p1 * p2 > 0) or (p3 * p4 > 0)):
        kolor = 'black'
    else:
        kolor = 'red'
    plotno.create_line(x1, y1, x2, y2, fill=kolor, width=3)
    plotno.create_line(x3, y3, x4, y4, fill=kolor, width=3)
    return

okno = Tk()
width=500
height=500
plotno = Canvas(okno, width=width, height=height, background='white')
plotno.grid(row=1,column=1)
przycisk = Button(okno,text='Losuj', command = Losuj, anchor=W)
przycisk.configure(width =10, activebackground = 'grey', relief = FLAT)
plotno.create_window(10,10, anchor=NW, window=przycisk)


okno.mainloop()