title: How to Annotate/Label an Object (Arrow) in VPython?
body: <p>I am using VPython to draw coordinate systems. </p>
  
  <p>Since I did not find any readily avalible coordinate system object, I thus draw three mutual-perpendicular arrows to represent the coordinate system as follows:</p>
  
  <pre><code>y = arrow(pos=(0,0,0), axis=(6,6,0), shaftwidth=0.00001, color=color.red)
  x = arrow(pos=(0,0,0), axis=(-6,6,0), shaftwidth=0.00001, color=color.green)
  z = arrow(pos=(0,0,0), axis=(0,0,-10), shaftwidth=0.00001, color=color.blue)
  </code></pre>
  
  <p>Problem is that I cannot label/annotate them. I can only distinguish them by color, which is not very convenient.</p>
  
  <p><strong>How can I write a <code>'x'</code> by the side of the <code>x object</code>?</strong></p>