title: Python 3D geometry: draw angles
body: <p>Is there any from to draw "the angle between 2 vectors in 3D" in python like this image:</p>
  
  <p><a href="http://intmstat.com/vectors/cosines.gif" rel="nofollow noreferrer">http://intmstat.com/vectors/cosines.gif</a></p>
  
  <p>,i.e., like this post: <a href="https://stackoverflow.com/questions/25227100/best-way-to-plot-an-angle-between-two-lines-in-matplotlib">Best way to plot an angle between two lines in Matplotlib</a> but in 3D.</p>
  
  <p>Thank you very much!
  Any advice will be greatly appreciated.</p>