[R] Split plot panel into rows with different columns

[Luigi Marongiu]

Hello,
I would like to draw 5 figures in the same plot. The layout is:
  first row: 1 column
  second row: 2 columns
  third row: 2 columns
I have used split.screen:
```
> split.screen(c(3, 1))       # split display into 3 screens
[1] 1 2 3
> split.screen(c(1, 2), screen = 2) # split second screen into two columns
[1] 4 5
> split.screen(c(1, 2), screen = 3) # split third screen into two columns
[1] 6 7
> screen(1)
> plot(classified$MR[classified$Class == "positive"] ~
+ classified$FCN[classified$Class == "positive"], cex=1.5, pch=16,
+ xlim=c(0,50), ylim=c(0,0.45),
+ xlab=expression(bold("FCN")), ylab=expression(bold("MR")))
Error in plot.new() : figure margins too large
```
Is this the correct syntax? Then I simply plot into each of the 7
screens. So the error is about margins/
Or is it simply that the layout is not correct?
Thank you