Recalling talk of visuals embedded in a track by electronic experimentalist Aphex Twin, Bastwood decided to take a closer look -

First I needed to extract the track from the Windowlicker CD, which was easy with CDex. The extraction of the whole track was not really necessary because the “face” is situated at the very end of the track, starting from the 5:27 mark and lasting for about 10 seconds. There are other “audio images” on this particular track as well (and one at the end of the first track), but the face is certainly the most exciting of them all.

After I had the wav-file, I used a program called Spectrogram to visualize the file. To my amazement, it worked, and I was soon staring at the “demon” face

… and Aphex isn’t the only one to use this technique – see spectrum visualizations from Plaid, Venetian Snares, and others along with more info here – The Aphex Face

Update: A commenter points out this video demonstration of the track being played -