pp.ellipse <-
function (center=c(0,0), a=1, b=1, phi=0, resolution=100) 
{
	# function that gives the x and y positions of an ellipse
	# placed in the public domain 2012 by Burns Statistics

	stopifnot(length(center) == 2, length(a) == 1, length(b) == 1,
		length(phi) == 1, length(resolution) == 1)
	tt <- seq(0, 2 * pi, length=resolution)
	x <- center[1] + a * cos(tt) * cos(phi) - b * sin(tt) * sin(phi)
	y <- center[2] + a * cos(tt) * sin(phi) + b * sin(tt) * cos(phi)
	list(x=x, y=y)
}
P.activepassive <-
function (filename = "activepassive.png") 
{
	if(length(filename)) {
		png(file=filename, width=512, height=530)
		par(mar=c(5,4, 0, 2) + .1)
	}

	plot(.5, .5, xlim=c(0,1), ylim=c(0,1), xlab='Effort', ylab='Turnover', 
		axes=FALSE, type="n", xaxs="i", yaxs="i")

	axis(1, at=c(0,.95), labels=c("0", "high"))
	axis(2, at=c(0,.95), labels=c("0", "high"))
	box(bty="L")

	text(.93, .93, "EXPENSIVE", cex=4, col="gold", 
		vfont=c("sans serif", "bold"), adj=1)
	text(.03, .08, "CHEAP", cex=4, col="gold", 
		vfont=c("sans serif", "bold"), adj=0)

	# active-passive boundary
	xs <- seq(.01, .75, length=100)
	lines(xs - .02, 3.5 * (xs^-.05 - .75^-.05))
	text(.28, .49, "active-passive boundary")
	arrows(.24, .47, .09, .39,, length=.1, lwd=2)

	# index funds
	lines(pp.ellipse(center=c(.2, .12), a=.1, b=.01), col="steelblue", lwd=2)
	text(.35, .22, "index funds", col="steelblue")
	arrows(.32, .2, .25, .14, col="steelblue", length=.1, lwd=2)

	# minimum variance funds
	lines(pp.ellipse(center=c(.1, .15), a=.01, b=.1), col="steelblue", lwd=2)
	text(.2, .32, "minimum variance", col="steelblue")
	arrows(.22, .3, .11, .23, col="steelblue", length=.1, lwd=2)

	# HFT
	lines(pp.ellipse(center=c(.9, .9), a=.05, b=.05), col="steelblue", lwd=2)
	text(.8, .78, "high frequency trading", col="steelblue")
	arrows(.84, .8, .87, .86, col="steelblue", length=.1, lwd=2)

	if(length(filename)) {
		dev.off()
	}
}