title: Lines dividing graphs using layout() in R
body: <p>I'm using layout() in R to produce a series of 9 graphs (in a 3x3 layout)</p>
  
  <pre><code>    m &lt;- rbind(c(1,2,3), c(4,5,6), c(7,8,9))
      layout(m)
  </code></pre>
  
  <p>I'm trying to put 2 vertical lines between the three columns in order to separate the columns from each other. box() is not appropriate as I want the rows to be linked and so don't want lines there, and I'm struggling to find any help using line() function and any ideas would be appreciated.</p>
  
  <p>Thanks</p>