title: Running turtles simultaneously with turtle graphics
body: <p>How can I make 4 different turtles move at the same time? Also, how to make a person shape for the <code>Turtle.shape</code>method? I know there's a Screen method called <code>register_shape</code>, but I couldn't find any documentation on it.</p>
  
  <pre><code>def turtles(self, base):
      self.t4.goto(self.tFirst)
      self.t1.goto(self.tSecond)
      self.t2.goto(self.tThird)
      self.t3.goto(self.tHome)
      if base &gt;= 2:
          self.t4.goto(self.tSecond)
          self.t1.goto(self.tThird)
          self.t2.goto(self.tHome)
      if base &gt;= 3:
          self.t4.goto(self.tThird)
          self.t1.goto(self.tHome)
      if base == 4:
          self.t4.goto(self.tHome)
  </code></pre>
  
  <p><code>tFirst</code>, <code>tSecond</code> an <code>tThird</code> are positions, and <code>t1</code>, <code>t2</code>, <code>t3</code>, <code>t4</code> are turtles. I want all of the turtles to move in unison.</p>