The idea of a polyphonic keyboard on wheel instruments derives from my studies about 12th century Organistrum.
This same model is suitable for the small wheel instruments depicted in XIII and XIV paintings and sculptures.
The three strings are tuned to the same pitch (C), eight tangents being distributed among them: two on the first string, three on the middle one and three on the third.
Thus it is possible to play not only a melody accompanied by drones, but some double stops (fourths and thirds) too.
I introduce you SONYA, the polyphonic symphonia.
Diapason: cm. 43