title: Multiple ggplots of different sizes
body: <p>It's relatively simple using <code>grid.arrange</code> in the <code>gridExtra</code> package to arrange multiple plots in a matrix, but how can you arrange plots (the ones I'm working on are from <code>ggplot2</code>) when some plots are intended to be larger than others? In base, I can use <code>layout()</code> such as in the example below:</p>
  
  <pre><code> nf &lt;- layout(matrix(c(1,1,1,2,3,1,1,1,4,5,6,7,8,9,9), byrow=TRUE, nrow=3))
   layout.show(nf)
  </code></pre>
  
  <p>what is the equivalent for <code>ggplot</code> plots?</p>
  
  <p><img src="https://i.stack.imgur.com/FdRRs.png" alt="enter image description here"></p>
  
  <p>Some plots for inclusion</p>
  
  <pre><code>library(ggplot2)
  p1 &lt;- qplot(x=wt,y=mpg,geom="point",main="Scatterplot of wt vs. mpg", data=mtcars)
  p2 &lt;- qplot(x=wt,y=disp,geom="point",main="Scatterplot of wt vs disp", data=mtcars)
  p3 &lt;- qplot(wt,data=mtcars)
  p4 &lt;- qplot(wt,mpg,data=mtcars,geom="boxplot")
  p5 &lt;- qplot(wt,data=mtcars)
  p6 &lt;- qplot(mpg,data=mtcars)
  p7 &lt;- qplot(disp,data=mtcars)
  p8 &lt;- qplot(disp, y=..density.., geom="density", data=mtcars)
  p9 &lt;- qplot(mpg, y=..density.., geom="density", data=mtcars)
  </code></pre>