Spectrogram #1

Ever the maverick, electronica fiend Aphex Twin made a track in 1999 that is often referred to as 'Formula', 'Equation' or 'Mathematical Equation' [its actual full title is the long-winded 'ΔMi−1=−αΣn=1NDi[n][Σj∈C{i}Fji[n − 1]+Fexti[(n−1)]'.]

The interesting part which specifically relates to visualizing music is that it was embedded with sound that would create an image when re-played as a spectrogram. At 5:30 on the above video you can see the appearance of a face - an image of Richard 'Aphex Twin' James.