tmpar <- par(mar=c(0,0,0,0))

plot(c(0,4.5),c(0,2.5),type="n",xaxt="n",yaxt="n",
	xlab="",ylab="")

tmp <- 1.75
circle(tmp,1.25,1.25,cen=0)
text(tmp,2,"target\npopulation")

circle(tmp+1.25,1,1,cen=0)
text(tmp+1.35,.5,"sampled\npopulation")

circle(tmp+1.1,1.3,.5,cen=0)
text(tmp+.9,1.3,"sample")

tmpx <- runif(30,-1,1)
tmpy <- runif(30,-1,1)
tmpp <- tmpx^2+tmpy^2 < 1
points(tmp+1.1+.5*tmpx[tmpp],1.3+.5*tmpy[tmpp],pch=5)

par(tmpar)