[R] Plotting multiple smooth lines on the same graph

[Eleni Rapsomaniki]

Hi

Say we have the following data sets:
d1=cbind(rnorm(100,1,1), rnorm(100,10,50))
d2=cbind(rnorm(100,5,1), rnorm(100,1,5))

I want to plot them both on the same graph with a curve fitted for each. 
I could call scatter.smooth to plot the first curve, but how do I add the
second?

scatter.smooth(d1)

Many thanks
Eleni Rapsomaniki