[R] overlapping plots

[Carlisle Thacker]

How to combine three plots so that they partially overlap?  As the data 
on all three are near the left side and top, it would be nice to draw 
the first, shift axes down and to the right and draw the second, and 
shift again to draw the third.

I could shift the data for the 2nd and 3rd plots and construct their 
axes by hand, but it would be great if R has an easier way.