title: How do I use gnuplot to plot a simple 2d vector arrow?
body: <p>This is my first time trying to use gnuplot, and I can't find any instructions on how to accomplish this. The closest I found was this:</p>
  
  <blockquote>
    <p><a href="http://gnuplot.sourceforge.net/docs_4.2/node259.html">http://gnuplot.sourceforge.net/docs_4.2/node259.html</a></p>
    
    <p>plot 'file.dat' using 1:2:3:4 with vectors head filled lt 2</p>
  </blockquote>
  
  <p>but I can't find any explanation about "file.dat".</p>
  
  <p>So can somebody give a simple example of how to draw a simple 2d vector arrow? Thanks.</p>