Empty graph sheet for linear interpolation (quantile calculation in histograms, ... ). R code:
> png("kuantil_kalkulurako_diagrama_hutsa.png")
> par(bty="l")
> x=c(20,28.17,40)
> y=c(552,861,1308)
>plot(x,y,xaxt="n",yaxt="n",xlim=c(15,45),ylim=c(450,1500),
pch=16,xaxs="i",yaxs="i",xlab="",cex.lab=0.8,ylab="")
> axis(1,at=c(20,28.17,40),labels=c("","",""))
> axis(2,at=c(552,861,1308),labels=c("","",""),las=2)
> polygon(c(20,40,40),c(552,552,1308),border=TRUE)
> a=c(20,20)
> b=c(450,552)
> lines(a,b,lty=3)
> c=c(0,20)
> d=c(552,552)
> lines(c,d,lty=3)
> e=c(28.17,28.17)
> f=c(450,861)
> lines(e,f,lty=3)
> g=c(0,28.17)
> h=c(861,861)
> lines(g,h,lty=3)
> i=c(40,40)
> j=c(450,1308)
> lines(i,j,lty=3)
> k=c(15,40)
> l=c(1308,1308)
> lines(k,l,lty=3)
> arrows(x0=30,y0=552,x1=30,y1=861,code=3,length=0.1)
> arrows(x0=42,y0=552,x1=42,y1=1308,code=3,length=0.1)
> arrows(x0=20,y0=500,x1=28.17,y1=500,code=3,length=0.1)
> arrows(x0=20,y0=480,x1=40,y1=480,code=3,length=0.1)
> dev.off()