[R] little subplot in corner

[Thomas Steiner]

I want to draw a little subplot ("overview") into my detailed plot. It
should be placed in say the top right corner and have the size of some
legend (like legend(x="topright", inset=0.03, ...)

#main plot
plot(rnorm(100))
#give little density in corner
plot(seq(-2,2,length=300),dnorm(seq(-2,2,length=300)),type="l")

I don't want something like par(mfrow=c(1,2)) as this gives subplots
of equal size.
I saw that gridBase is very flexible, but could not find a suitable example.

Thanks for help,
Thomas