Nearly 500 years after da Vinci sketched his plans for a musical instrument he dubbed the Viola Organista, Polish concert pianist Slawomir Zubrzycki spent more than 5,000 hours making da Vinci’s idea a reality.
http://www.classicalmpr.org/story/2015/07/17/listen-to-the-instrument-da-vinci-invented-but-never-got-to-hear