title: Tkinter window not opening
body: <p>I was trying to create a simple moving block using tkinter in Python 3, and everything was working until I imported time. The window now won't open. I've tried removing the import, and it doesn't help. This is my code:</p>
  
  <pre><code>from tkinter import *
  import time
  
  canvas_height = 400
  canvas_width = 600
  canvas_colour = "grey50"
  moveBoolean = "True"
  
  def move():
      global moveBoolean
      while moveBoolean == "True":
          time.sleep(0.005)
          canvas.move(square, 90, 90)
          time.sleep(0.005)
          canvas.move(square, 180, 180)
          time.sleep(0.005)
          canvas.move(square, 50, 100)
  
  window = Tk()
  
  canvas = Canvas(bg=canvas_colour, height=canvas_height, width=canvas_width, highlightthickness=0)
  canvas.pack()
  
  square = canvas.create_rectangle(50, 50, 50, 50, width=50, fill="black")
  
  move()
  
  window.mainloop()
  </code></pre>