biplot <- macro("
@X <- $1
@rlabs <- $2
@clabs <- $3
@X <- @X - tabs(@X,mean:T)'
@p <- ncols(@X)
@s <- svd(@X,all:T)
@p1 <- @s$leftvectors[,1]*@s$values[1]
@p2 <- @s$leftvectors[,2]*@s$values[2]
@v1 <- @s$rightvectors[,1]
@v2 <- @s$rightvectors[,2]
@f <- vector(max(@p1)/max(@v1),max(@p2)/max(@v2),min(@p1)/min(@v1),min(@p2)/min(@v2))
@f <- @f[@f > 0]
@f <- min(@f)
@v1 <- @v1*@f
@v2 <- @v2*@f
@blank <- \" \"
chplot(@p1,@p2,@rlabs,xlab:@blank,ylab:@blank,show:F)
for(@i,run(@p)) {
	addpoints(@v1[@i],@v2[@i],symbol:@clabs[@i],show:F)
	addlines(vector(0,@v1[@i]),vector(0,@v2[@i]),show:F)
;;
}
showplot(xmin:?,ymin:?,xmax:?,ymax:?,$K)",dollars:T)