[R] watermarks

[Karla Meurk]

Hi, I would like to plot a graph which sits in the background as a 
watermark with other plots in the foreground - on top.  I have looked 
through the threads on the r-project website but they seem to concern 
background colours rather than actual background plots.  I have also 
searched through the demo's and pars but can't find any eg's

any ideas - I only want to plot a simple graph using pie.chart()

Thanks

Carla