Sun Boxes is an installation that is made of a solar-powered series of 20 speakers, each continuously playing a different guitar note in a looped set. Together, these guitar notes make a Bb chord. Because the loops are different in length, once the piece begins they continually overlap and play some truly beautiful music — all from nature. Watch it in action:

http://www.youtube.com/watch?v=988tCKKKc_8

Thanks, Craig!