The background texture that is used in these pages is a fragment of one of Nancarrow's "Studies for Player Piano" as it looks when transcribed to a MIDI score. This MIDI score was provided by Trimpin, who made MIDI transcriptions of all of the "Studies for Player Piano." Trimpin also created a device that fit over the keyboard of a standard piano that would play these MIDI transcriptions. Below is a photo of that device mounted on a piano.
Trimpin and Nancarrow at Yerba Buena Center for the Arts