success1 <- c( 8, 1)
  total1   <- c(10,10)
  success2 <- c( 6, 3)
  total2   <- c( 6,17)
  
  printaddvec <- function( vec1, vec2, ...) {
    segments( vec1[1], vec1[2], vec1[1]+vec2[1], vec1[2]+vec2[2], lty=3, ... )
    segments( vec2[1], vec2[2], vec1[1]+vec2[1], vec1[2]+vec2[2], lty=3, ... )
  
    arrows(0,0, vec1[1], vec1[2], angle=20, code=2, lwd=2, ...)
    arrows(0,0, vec2[1], vec2[2], angle=20, code=2, lwd=2, ...)
    arrows(0,0, vec1[1]+vec2[1], vec1[2]+vec2[2], angle=20, code=2,
           lwd=2, lty=2, ...)
  
    # Redraw the end of the arrows
    arrows(0.99*(vec1[1]+vec2[1]), 0.99*(vec1[2]+vec2[2]),
           vec1[1]+vec2[1], vec1[2]+vec2[2], code=2, lwd=2, angle=20, ...)
  }
  
  postscript("simpsons-vector.eps", paper="special", height=5, width=5,
             horizontal=F)
  par(xaxs="i")
  par(yaxs="i")
  par(cex=1.2)
  par(las=1)
  par(mgp=c(2.5 ,1 ,0))
  par(mar=c(4.1, 4.1, 0.6, 0.6))
  
  plot(0, type="n", xlim=c(0,25), ylim=c(0,10), pty="s", xlab="Total", ylab="Successes")
  
  printaddvec( c(total1[1], success1[1]), c(total1[2], success1[2]), col="blue")
  printaddvec( c(total2[1], success2[1]), c(total2[2], success2[2]), col="red")
  
  text(total1[2], success1[2]+0.0, "1", pos=4, col="blue", cex=1.2)
  text(total2[2], success2[2]+0.0, "1", pos=4, col="red",  cex=1.2)
  text(total1[1]+0.0, success1[1], "2", pos=3, col="blue", cex=1.2)
  text(total2[1]+0.0, success2[1], "2", pos=3, col="red",  cex=1.2)
  text(sum(total1), sum(success1)+0.0, "+", pos=3, col="blue", cex=1.2)
  text(sum(total2), sum(success2)+0.0, "+", pos=3, col="red", cex=1.2)
  
  dev.off()