its a roll of paper, with black dots, as the roll moves, the black marks activate photosensitive switches and these in turn, activate the individual air releases that are placed in each arm ... so its like a giant scottish bagpipe that makes this immense soundscape that is ... this installation ..
amazing ....
all found here ,....
http://www.wonderhowto.com/wonderment/building-sized-berorgan-emits-heavenly-music-and-farts-0113557
