from tkinter import*
tk=Tk()
tk.geometry("1280x720+400+300")
tk["bg"]="grey"
label1=Label(bg="white")
label1.place(x=50, y=50, width=250, height=250)
label2=Label(bg="black")
label2.place(x=150, y=50, width=50, height=250)
label3=Label(bg="black")
label3.place(x=50, y=150, width=250, height=50)