title: How to plot two 3D graphs on the same plot in R
body: <p>I'm using the <code>plot3d</code> function in the library <code>rgl</code>. Suppose my data looks something like this.</p>
  
  <pre><code>    x &lt;- c(1,2,3,4,5)
      y &lt;- c(4,2,1,4,2)
      z &lt;- c(2,2,4,5,1)
  
      x2 &lt;- c(1,5,2,3,4)
      y2 &lt;- c(2,3,4,1,2)
      z2 &lt;- c(3,4,2,3,1)
  
      plot3d(x, y, z)
      plot3d(x2, y2, z2)
  </code></pre>
  
  <p>Using the commands above would give me 2 separate plots. How can I plot both datasets on the same graph? Also I would like to use different symbols for the points in the two different data sets.</p>