1with(airpc, { 2pc <- cbind(Comp.1, Comp.2) 3pc1 <- pc[Period==1,] 4pc2 <- pc[Period==2,] 5pc3 <- pc[Period==3,] 6xlim <- range(Comp.1) 7ylim <- range(Comp.2) 8 9par(mfrow=c(2,2)) 10plot(Comp.1, Comp.2, xlim = xlim, ylim = ylim, main="1914-84") 11lines(xlim, c(0,0), lty=2) 12lines(c(0,0), ylim, lty=2) 13plot(pc1, xlim = xlim, ylim = ylim, main="1914-35") 14lines(xlim, c(0,0), lty=2) 15lines(c(0,0), ylim, lty=2) 16plot(pc2, xlim = xlim, ylim = ylim, main="1936-55") 17lines(xlim, c(0,0), lty=2) 18lines(c(0,0), ylim, lty=2) 19plot(pc3, xlim = xlim, ylim = ylim, main="1956-84") 20lines(xlim, c(0,0), lty=2) 21lines(c(0,0), ylim, lty=2) 22par(mfrow=c(1,1)) 23}) 24