title: How it is possible to be a circle in python?
body: <p>Here is the code In the book Thinkpython 2e.</p>
  
  <pre><code> import turtle
   import math
  
   bob = turtle.Turtle()
  
   def polygon(t, n, length):
       angle = 360 / n
       for i in range(n):
           t.fd(length)
           t.lt(angle)    
  
   def circle(t, r):
       circumference = 2 * math.pi * r
       n = 50
       length = circumference / n
       polygon(t, n, length)
  
   circle(bob,50)
   turtle.mainloop()
  </code></pre>
  
  <p>I don't understand how it is possible to be a circle, I think it will be a 50-sides polygon, am i right?</p>