who has been described as “the most inventive and influential figure in contemporary electronic music,” appears to have sneaked the digital image of a devilish face into at least one of his songs.

The spooky image of a creature with a diabolical grin has been accidentally discovered on Aphex Twin's Windowlicker EP, a 1999 hit.

The sinister face is revealed when the song is played on a computer through special software that visualizes sound waves.

Just like the backward messages on vinyl LPs, the face is secretly encoded in the actual sound waves of the music. It isn't a separate file on the CD. The image is the aural equivalent of steganography: the practice of hiding secret messages and watermarks in images.

The existence of the image has not been publicized by Aphex Twin or his record label.

It seems to have been discovered accidentally by an electronic musician who calls himself Chaos Machine. Chaos Machine wasn't available for an interview, but according to his website, he was playing around with WinAmp one evening when he spotted the diabolical face.

His discovery can be reproduced with a sample of the song and some spectrographic software, which displays the different frequencies of the song as a graph against time. The image doesn't appear in an MP3 file of the song; the compression algorithm destroys the image.

Chaos Machine's discovery is starting to make the rounds on the Internet, and is fast becoming part of the folklore surrounding hidden messages in pop music.

But it appears Chaos Machine was a bit too quick off the mark. The song does indeed contain the image of a face, but not a demonic one. It's Aphex Twin himself – or Richard James, as he's known to his parents.

The real image was discovered by a 19-year-old named Jarmo Niinisalo, who tweaked the settings in his spectrographic software to reveal James' grinning fizzog. The procedure is described on Niinisalo's website.

Niinisalo also discovered three more pattern-like images embedded in songs on the Windowlicker EP. None of them is sinister.

James apparently created the hidden pictures in his songs using a clever piece of synthesizer software called MetaSynth.

MetaSynth is a Mac-only application that can take any image and generate sounds from it. The software was widely used in The Matrix to accompany the movie's mind-bending bullet-speed special effects.

Most musicians who use the application input abstract pictures because they can generate meaningful sounds. Scanned photographs tend to create a kind of discordant, metallic scratching. The program's creator, Eric Wenger, ran pictures of factories through it for some industrial techno compositions.

However they sound, images are readily recreated by running the sounds they generate through any spectrograph software.