title: Tkinter Canvas creating rectangle
body: <p>In python, tkinter, I'm trying to make a game that involves creating shapes onto a canvas. For example, I want a red rectangle to appear over my canvas image. When I execute my code, the rectangle you see is about 1 pixel in size, and I'm not sure why and how it got like that. Here's my code:</p>
  
  <pre><code>from tkinter import *
  root = Tk()
  root.geometry("500x900")
  canvas = Canvas(root, width=550, height=820)
  canvas.pack()
  png = PhotoImage(file = r'example.png') # Just an example
  canvas.create_image(0, 0, image = png, anchor = "nw")
  
  a = canvas.create_rectangle(50, 0, 50, 0, fill='red')
  canvas.move(a, 20, 20)
  </code></pre>
  
  <p>Hope this can be resolved.</p>