par(lwd=4)
pie(1,clock=T,labels=NA,col=c("white"),radius=.805)
par(new=T)
pie(c(1,3),clock=T,labels=NA,col=c("gray60","white"),lty=0)
arrows(0,0,0,.8)
dev.copy2eps(file="wh1.eps")
dev.off()

par(lwd=4)
pie(1,clock=T,labels=NA,col=c("white"),radius=.805)
par(new=T)
pie(c(1,1),clock=T,labels=NA,col=c("gray60","white"),lty=0)
arrows(0,0,0,.8)
dev.copy2eps(file="wh2.eps")
dev.off()