[R] 3 curves / 1 plot

[Michel PETITJEAN]

I am a new user of R.
Please does somebody knows how to plot 3 datasets
(x1,a1),...,(xn,an), (x1,b1),...,(xn,bn), and (x1,c1),...,(xn,cn)
on a single x,y plot, each of the three datasets being plotted with
its own character pch() ?
(three calls to plot() erase the two first datasets).
Thank you very much.

Michel Petitjean,
DSV/iBiTec-S/SB2SM (CNRS URA 2096), CEA Saclay, bat. 528,
91191 Gif-sur-Yvette Cedex, France.
Phone: +331 6908 4006 / Fax: +331 6908 4007
E-mail: michel.petitjean at cea.fr
http://petitjeanmichel.free.fr/itoweb.petitjean.html