Everyone loves sine waves.
In the above .swf, a Pixel Bender kernel is summing three sine waves at various frequencies and amplitudes, and drawing it in three colors. Each pixel gets either black, or one of the three colors, depending how close it is to the waveform.
The distance to the waveform is measured only vertically, though, so the peaks get extended in a strange, sort of 60’s/70’s op-ish way.