Nancarrow was a wonderful maniac. He hand cut pianola rolls as he realised that - as a sequencer - it was capable of playing things beyond the realms of human capabilities, with huge musical leaps and speeds that are utterly unplayable. He would also (occasionally) play three or four pianolas at the same time and hoped they would coincide.
I bought his recordings from Recommended Records in London by mail order, who were selling some seriously odd stuff at the time (RIO, musique concrete, etc). Chris Cutler sent me a note inside one of the records with the words 'congratulations - this music is impossible'. Coming from a guy who played in Henry Cow, that's high praise indeed.
After listening to Nancarrow's music the works of The Residents seemed pretty pedestrian.