plot(c(-1,6),c(-2,4),type="n",xlab="",ylab="",asp=1)
abline(h=seq(-2,4,1), v=seq(-1,6,1), col="grey60",lty=3)
axis(1,pos=0); axis(2,pos=0); points(3,1)
symbols(3, 1, circles=2, inches=FALSE, add=TRUE)