The Aphex Face. Is it audio steganography or is it art?
It is an audio/visual effect created by Aphex Twin, on the 1999 EP Windowlicker. The last 10 seconds or so of track 2 contain an audio representation of Richard D James' face.
This image can be viewed by extracting the audio data to a .wav file and subjecting it to spectral analysis. Two easy ways to do this on a PC are through any voiceprint plugin for Winamp, or "Spectral View" in CoolEdit Pro.
It was apparently done on a Macintosh using a piece of software called Metasynth, but similar effects can be achieved on a PC using Coagula, which can be found at http://hem.passagen.se/rasmuse/Coagula.htm