Image from Youtube
It's Easter Sunday, and that means Easter Eggs. But while to a majority of the holiday's celebrants this means Cadbury eggs hidden in the nooks and crannies of gardens, to a smaller number of people, "easter eggs" are a euphemism for the little secrets found in media, such as albums and tracks, including one particularly notable tune by Richard D. James, aka Aphex Twin.
The track commonly referred to as "Equation" (its literal title is "ΔM__i_−1 = −αΣn=1_N__D__i_[n][Σj∈C[i]_F__ji_[_n − 1] + Fext_i_[n−1]]" but try saying that out loud) appeared as a B-side to James famous 1999 track "Windowlicker." As pure audio it comes off as a very Jamesian beat and soundscape experiment. For the composition, however the infamously trickstery producer used an early Mac synth program called MetaSynth that converted images to sound. When "Equation" is played through a spectrogram, a visage of James's face unexpectedly appears near the end. It's even creepier when you think that the face was programmed first as sound, which makes a banshee-like screech and hiss as the track winds to an end.
While James's easter egg might win the award for "most well-conceived and executed," other notable easter eggs in electronic music include Nine Inch Nails's "Erase Me" message that can be heard if you fast-forward the track "Erased, Over, Out," (works best on CD, honestly), and musician Mike Oldfield's synthesizer morse coded messages to Virgin Records founder Richard Branson that can be heard on his album Amarok.