File:Acf.svg

Summary
An image of random numbers, with a hidden sine function, with a wavelength every 10 units. The bottom image shows the autocorrelation.

Made using R:

library(RSvgDevice) x <- rnorm(100) + sin(2*pi*1:100/10) devSVG("acf.pdf", width=3, height=4) par(mfrow=c(2,1), mar=c(3.5, 3.5, 0.5, 0.5), mgp=c(2, 0.8, 0), cex=.7) plot(x, type="o", col="blue", main=NA) acf(x, 100, main=NA) dev.off

Minor edit for dashed line in bottom figure using Inkscape.