Leonardo da Vinci created a lot of blueprints for a lot of gadgets. This is one of them: the viola organista. It is a piano-violin hybrid. He never built it, but the instrument looks just like a piano, and plays like one but sounds like a church organ but not quite either.

Polish concert pianist Slawomir Zubrzycki built the instrument from da Vinci's original plans and unveiled it to a live audience at Poland's Academy of Music. Check it out below: