Python: Figuras en ventanas hijas

# -*- coding: utf-8 -*-from Tkinter import *
VentanaPrincipal= Tk()
VentanaPrincipal.title("Ventana Principal")
VentanaPrincipal.config(bg="gold")
VentanaPrincipal.geometry("500x500")

def ocultar(ventana):ventana.destroy()
def ejecutar(f): VentanaPrincipal.after(200, f)

def mostrarcirculo():
    Vhija= Toplevel(VentanaPrincipal)
    Vhija.title("CIRCULO")
    Vhija.protocol("WM_DELETE_WINDOW", "onexit")
    Vhija.config(bg="black")
    Vhija.geometry("500x500")
    Circulo= Canvas(Vhija,width=300, height=210, bg='blue')
    Circulo.pack(expand=YES, fill=BOTH)
    Circulo.create_oval(10, 10, 400, 400, width=5, fill='White')
    BotonCirculo1= Button(Circulo, text="ocultar ventana", command=lambda: ejecutar(ocultar(Vhija)))
    BotonCirculo1.grid(row=1, column=3)
    Vhija.deiconify()

def mostrarrectangulo():
    Vhija2= Toplevel(VentanaPrincipal)
    Vhija2.title("RECTANGULO")
    Vhija2.protocol("WM_DELETE_WINDOW", "onexit")
    Vhija2.config(bg="black")
    Vhija2.geometry("500x300")
    Rectangulo= Canvas(Vhija2,width=300, height=210, bg='white')
    Rectangulo.pack(expand=YES, fill=BOTH)
    Rectangulo.create_rectangle(10, 10, 410, 200, width=5, fill='gold')
    BotonRectangulo1= Button(Rectangulo, text="ocultar ventana", command=lambda: ejecutar(ocultar(Vhija2)))
    BotonRectangulo1.grid(row=1, column=3)
    Vhija2.deiconify()

def mostrarlineas():
    Vhija3= Toplevel(VentanaPrincipal)
    Vhija3.title("LINEAS")
    Vhija3.protocol("WM_DELETE_WINDOW", "onexit")
    Vhija3.config(bg="black")
    Vhija3.geometry("300x300")
    linea= Canvas(Vhija3,width=300, height=210, bg='white')
    linea.pack(expand=YES, fill=BOTH)
    linea.create_line(0, 200, 200, 0, width=10, fill='blue')
    linea.create_line(0, 0, 200, 200, width=10, fill='blue')
    Botonlinea= Button(linea, text="ocultar ventana", command=lambda: ejecutar(ocultar(Vhija3)))
    Botonlinea.grid(row=1, column=3)
    Vhija3.deiconify()

boton1= Button(VentanaPrincipal, text="CIRCULO", command=lambda: ejecutar(mostrarcirculo()))
boton1.grid(row=1, column=1)
boton2= Button(VentanaPrincipal, text="RECTANGULO", command=lambda: ejecutar(mostrarrectangulo()))
boton2.grid(row=1, column=2)
boton3= Button(VentanaPrincipal, text="LINEAS", command=lambda: ejecutar(mostrarlineas()))
boton3.grid(row=1, column=3)
boton4= Button(VentanaPrincipal, text="Cerrar Ventana Principal", command=lambda: ejecutar(ocultar(VentanaPrincipal)))
boton4.grid(row=1, column=5)
VentanaPrincipal.mainloop()