f.pack(side=LEFT, expand=1)
f3 = Frame(f, bg='red', width=500)
f3.pack(side=LEFT, expand=1, pady=50, padx=50)
f2 = Frame(root, bg='black', height=100, width=100)
f2.pack(side=LEFT, fill=Y)
b = Button(f2, text='test')
b.pack()
b = Button(f3, text='1', bg='red')
b.grid(row=1, column=3)
b2 = Button(f3, text='2')
b2.grid(row=1, column=4)
b3 = Button(f3, text='2')
b3.grid(row=2, column=0)
root.mainloop()
Grid within a frame?