So a polish fellow by the name of Slawomir Zubrzycki has built a working example of a concept that Leonardo Davinci conceptualized in his Codex Atlanticus. A stringed instrument, bowed with a set of foot cranked rosin wheels, not unlike a hurdy gurdy. But the strings are not engaged with the wheels until a key is struck (vs a Hurdy Gurdy where the strings are in contact with the wheel and the keys change which notes are played). This allows keyboard ranges of notes/octives BUT with stringed instrument sound/vibration. Quite interesting I think. Lovely to see such a thing created in wood and brass. 3 years and 5000 hours is quite a piece of work.